pterodectyle

 

Female grizzly vs bison

"Its an account of a female grizzly attacking a young bull bison observed by TRAVIS WYMAN, Bear Management Office, at Yellowstone -

"I observed the incident from the road on the west sideof the Yellowstone River near the outlet of YellowstoneLake (elevation 2,371 m) on the morning of 23 September2000. I was observing a grizzly bear with 2 cubs-ofthe-year that were digging for pocket gophers (Thomomystalpoides) in a meadow 300–400 m from the Lake Lodge.This family group had been frequenting the area throughoutthe summer. At approximately 1200 hours, the bearsbegan walking northeast along the shore of Yellowstone Lake toward the Yellowstone River outlet at Fishing Bridge. At approximately 1300, the bears emerged onto the road at Fishing Bridge Junction and crossed to the north side. The bears continued walking north in a direction that would have taken them past a young adult bull bison lying under a tree 15 meters from the road. The bison stood up abruptly when the bears were approximately 5 meters away. When the bison stood up, the bears appeared startled. The adult female, then the cubs, stood up on their hind legs and looked at the bison. The bison stood in an alert posture with his tail raised and head down.
After a few seconds, the adult bear lunged toward the bison.
The bison immediately turned away and began trotting east, up slope along a bench directly above the road heading toward Fishing Bridge. The adult bear loped after the bison at less than full speed.
I drove east along the road, observing the movement of the bears and bison approximately 15 meters away. After trotting about 50 m, the bison broke into a full run. The adult bear then chased the bison at full speed. At the crest of the hill above the Yellowstone River, the bear swiped its paw across the hindquarters of the bison, knocking the bison’s back legs out from under it. The bison began to slide down the steep embankment of the hill on its back. After striking a tree with considerable force on its front quarters, the inverted bison continued to slide toward a pedestrian boardwalk at the base of the hill. The grizzly leaped onto the stomach of the inverted bison and skidded down the hill on top of it while attempting to bite at the bison’s neck. The bear and bison came to a stop at the base of the hill on the pedestrian boardwalk. The bear continued to bite and pull at the bison’s neck while the bison tried to get to its feet. The bison managed to stand and struggled to remain standing, but the bear continued to pull the bison back down to the ground. When the bison did stand, its hind legs buckled under its own weight. The bear took advantage of this and jumped onto the back of the bison, biting and clawing at its back, inflicting a number of bite and claw wounds around the bison’s hump and lower back. With a quick head motion, the bull managed to free itself from the bear and stand up a second time. At this time, I observed that the bison’s left front leg was broken. This injury may have occurred when the bison slammed into the tree while sliding down the steep hill. The bison continued attempts to stand and fought off the bear with its head and horns for several minutes. The bear stood up on its hind legs and swiped at the bull’s head with its paws. The bison reacted by rearing up, which caused it to slide backward into a ditch adjacent to the Fishing Bridge boardwalk. Being in the ditch appeared to put the bison in a better position to fend off the bear with its head and horns.
At this time the 2 cubs, which had been observing their mother from on top of the hill, came down and reunited with her near the bison. The bison continued to struggle to keep up-right and bled profusely from its back and hindquarters. The adult bear attacked the bison several more times, but the bison was able to use its head and horns to repel the attacks. The cubs did not participate in these attacks but remained nearby. On 5 occasions the bears left the area and were no longer visible to me, then came back and the adult attacked the bull again, but was unable to kill it. The interval between attacks increased from approximately 5 minutes to several hours between return visits.
At approximately 1800 the bears left and did not return, enabling me to investigate the bison in the ditch. The bison was startled upon my approach and attempted to climb out of the ditch. It fell down and was unable to pull itself out of the mud. Due to the proximity of the bison to the main road and concerns for the safety of visitors and a construction crew working on the road bridge adjacent to the attack site, park management decided to dispatch the bison and move the carcass. After shooting the bison, the carcass was moved 0.9 km away to a location remote from public use areas. Managers hoped that the bear family group would follow the scent trail to where the carcass was disposed and scavenge the remains."

http://www.nrmsc.usgs.gov/products/Predation_Papers.pdf

Credited to taipan. The bison didn't die but it was an impressive feat on the female grizzlies part. A male would likely do better ;).

ursusarctos

 

Eh, due to lack of anything better at the moment, anf the fact that I'd like to at least post something, I'll add what I posted in my thread titled "Bear intellegence" on AVA:

In one section in the Great Bear Almanac describing Bears generally (meaning not only Brownies), it mentions the following:

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Court with demonstrable affection

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Spank their young

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High degree of unpredictability

The first is something very rare amoung many wild animals; the second is something that also clearly shows "teaching" of behavior, etc, and should show some depth in behavior, with the last showing something similar, mostly by suggestling limitted number of instinctive behaviors.

Here is more from the Great Bear Almanac:

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Intelligence
Bear intelligence is difficult to assess, and should not be compared or measured in human terms. Bears are considered by scientists and naturalists to be highly intelligent animals, based on their ability to learn rapidly and to reason.
Curiosity, coupled with an excellent memory, may be the key to a bear's “intelligence.” It leads to learning and knowledge, which is the basis of survival-adaptability to environmental changes and unusual circumstances. Bears learn and remember from a single experience-a food source, a threat, a trap, or a rifle shot.
“Bears are highly intelligent and individualistic,” relates Terry Domico in Bears of The World, “and are capable of nearly as many responses in a given circumstance as a human. Some biologists believe the highly adaptable brown bear is intelligent enough to be ranked with primates, like monkeys and baboons.”
Bears display many “intelligent” actions that include:
# Hiding dark nose with a paw (polar bear)
# Hiding behind ice blocks (polar bear)
# Learning quickly in "training" situations
# The display of a cunning mind
# Sneaking
# Bluffing
# Concealing self in ambush; hiding from humans
# Beginning hibernation during heavy snowfall to conceal tracks to den
# Choosing alternatives
# Adapting to other influences (including human, if allowed)
# Baiting other animals (polar bear)
# Resourcefulness
# Capacity to reason
# Avoiding problems
# Outwitting humans
# Calculating
# Retreating in the face of great odds (human impacts)
# Hiding tracks (jump to side, step on own tracks, wade in stream)
# Using tools
# Backtracking

The Bear “reached even deeper into his bag of tricks and came out with something new-backtracking,” relates American lack bear biologist Gary Alt, in Stephen Herrero's Bear attacks, “...suddenly, his tracks simply vanished. There were no rocks, no water, nothing to conceal his tracks. I went back to his tracks. This time I noticed there were toe marks at both ends, even though there was no evidence...to indicate the bear had turned around. I followed them back about 50 yards and found where the bear had jumped off the main trail, walking away in a direction perpendicular to his old tracks.”
Strong circumstantial evidence has existed for over two hundred years that polar bears use ice blocks or rocks to kill seals. Bear biologist C. Jonkel tells of polar bears using small rocks to spring traps.
Studies at the University of Tennessee psychology department indicate that American black bears are very intelligent, probably more so than many other mammals of the world. They open door latches and screw-top jars, recognize uniforms and vehicles. On one occasion, two five-year-old American black bears ran to a group of humans for security when a larger bear arrived. Enos Mills noted in The Grizzly-Our Greatest Wild Animal

In The Wild Bears, by John Laycock:

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How Smart
Is the Grizzly?
Those who know the grizzly bear well generally cridit it with being intelligent and resourceful, quick to learn and slow to forget. There was a time, in scientific circles, when wild animals were thought to lack the ability to reason and all their actions were credited to instinct and nothing more. This belief supported man's sense of superiority, flattered him, and left him convinced that he was unique in the world where no other creature possessed the ability to figure anything out for itself. Charles Darwin's theories began to turn this around, and we have come to understand that other animals, while they may lack the highly developed brain of the human, do possess intelligence. The bears seem to rank well up the ladder in intelligence and sometimes demonstrate what appears to be a remarkable capacity to reason.
This has been noted by many who knew bears from first-hand experience. Harold McCracken, naturalist, explorer, and long-time student of the grizzly bear in it's natural haunts, wrote in his notable book The Beast that Walks Like Man, “The better acquainted I have become with grizzlies, the higher opinion I have of them; and this applies to their intelligence as well as their dispositions.”
“I would give the grizzly first place in the animal world for brainpower,” Enos Mills adds.
Naturalist David Star Jordan classed the grizzly bear as mentally superior to the dog, horse, and gray wold, and said that the grizzly has, not only instinct, ut also the power to reason. Seldom does anyone call the animal dumb. Theodore Roosevelt, who knew both his share of grizzlies and the men who spent much of their lives chasing them, said, “The grizzly is a shrewd beast that shows the usual bear-like capacity for adapting himself to changed conditions.”
The evidence is found in accounts of the great bear's skill at avoiding trouble and outwitting people. William H. Wright, who tracked grizzlies for many years wherever he could find them, recorded the story of the most remarkable grizzly he ever encountered.
“The grizzly bear,” said Wright, “far excels in cunning any other animal found throughout the Rocky Mountains, and indeed for that matter, he far excels them all combined.” Wright's candidate for the head of the class was a grizzly living in the Bitterroots at the time the naturalist accompanied a hunting party into those mountains.
The party camped on a tributary of the Clearwater where one of the hunters had spotted a giant silvertip bear. He killed an elk, and after the elk was dressed, the scraps were carried to a gully a mule or so from camp. Here the group built a log pen, tossed the remains of the elk into it as bait, and set their trap where the grizzly, if he came, should step right into trouble.
When Wright returned to the site, it looked as if a tornado had touched down. The pen was torn down and the logs heaped up over the trap which had not been touched. The bait, however, had been deftly removed.
Wright looked around. “Fifty feet away,” he wrote, “I saw a large pile of moss and leaves scraped together and beside it a bed where the bear had been lying.” Wright found that the moss covered what was left of the bait and this gave them an idea. They rescued the trap from beneath the heap of logs and made a new set in the bear's pile of leaves and moss, then tossed pieces of the elk meat around the set, congratulated themselves, and left to await the bear's return.
“That night,” according to Wright, “the bear came again, picked up all the loose meat, but touched nothing under the moss.”
The audacity of this elusive grizzly became almost a personal affront to members of the hunting party. About the time the grizzly frustrated the trappers in the second attempt, three members of the party shot three elk, a cow, calf, and bull. They decided to divide the meat between themselves and the local monarch that was making fools of them. They would use the bull, plus the remnants of the other two elk, as bait for the bear.
Some distance upriver from camp, they found the perfect place for their next attempt on the grizzly bear's life. An almost vertical gully reached from the top of the bank to the water's edge a hundred feet below. If the bear were to claim the meat he would have to negotiate a constricted passage between a log jam and a rock outcropping. It was here that the hunters rolled the excess elk meat down the slope.
The first night they set no trap but were content to allow the grizzly to find the meat and claim it. The following morning they were encouraged because they could read in the bear's tracks the story of what he had done. After eating all he wanted, he had dragged the remnants of the bait together in one place and covered them with dirt and leaves. He would be back. They promptly set bear traps around the bait, taking full precautions to hide evidence of their work. Again, the bear easily avoided the traps.
Members of the party, after again measuring the animal's giant track, wanted more than ever to take this smart old bear. By now, they were down to the final days of their hunt, and some of the group decided to rig a set gun, or spring gun, for the bear.

SET GUNS AND BEAR TRAPS
This brand of guerrilla warfare, using an untended gun with a string attached to the trigger against the grizzlies, was not an uncommon practice in those times. There was apparently little question about whether or not a set gun was fair to the game or even to some wandering human it might unintentially kill. There were no early laws to protect either bears or people against such booby traps, and some considered any tactic fair against bears. Not only set guns, but also the massive bear traps so commonly used, posed an ever-present threat to human life. Theodore Roosevelt often discussed the danger with western outdoorsmen and once wrote about it.
“There is, however”, said Roosevelt, “one very real danger to which the solitary bear-trapper is exposed, the danger of being caught in his own trap. The huge jaws of the gin are easy to spring and most hard to open. If an unwary passerby should tread between them and be caught by the leg, his fate would be doubtful, though he would probably die under the steady growing torment of the merciless iron jaws, as they pressed ever deeper into the sore flesh and broken bones. But if caught by the arms, while setting or fixing the trap, his fate would be in no doubt at all, for it would be impossible for the stoutest man to free himself by any means. Terrible stories are told of solitary mountain hunters who disappeared, and were found years later in the lonely wilderness, as mouldering skeletons, the shattered bones of the forearms still held in the rusty jaws of the gin.”
As the members of Wright's hunting party prepared their set gun reception for the big bear, Wright himself an outspoken admirer of the grizzly, may have had reservations. Nonetheless, he joined in the plan. The gun was set with the butt against a rock and the muzzle pointing at the trail the bear must follow, or at least the trail they thought he would follow. A silk fishing line, tied to the trigger, stretched across the bear's trail.
Then a second gun was rigged with a line a dozen feet from the first and parallel to it, leaving the bear a narrow pathway between the log jam and the rock outcropping which would help guide him to his fate. As the hunters viewed it, the big grizzly had only two choices. He could either give up his idea of elk for supper, or he could stumble across the strings and shoot himself in the side.
No one heard a gun fire during the night, so the hunters went the following morning to see what had happened. The tracks showed plainly that the grizzly had approached the silk string and stopped. When he tried to reach the bait from another direction, he again came to the string and suddenly stopped. Finally, instead of leaving hungry and frustrated, he climbed over the rock and worked his way from ledge to ledge until he could come down to the bait and eat in safety. Then he backtracked and departed by the sage path he had worked out. The hunter never saw him. Wright called this, “as wonderful a record of animal sagacity as I have ever seen.”
This bear's achievement becomes more believable when compared with the case reported by Enos Mills for about the same period. Mills wrote, “Formerly it was not difficult to trap a grizzly. But he quickly learned to avoid the menace of traps. The bear sees through all the camouflage of the trapper. Deodorized and concealed traps, traps near the bat and far from it, traps placed singly and in clusters-these, and even the slender concealed string of a spring gun he usually detects and avoids.”
Mills once had the opportunity to accompany a trapper who set out to take a big grizzly that ranchers had identified as an outlaw cattle stealer. The ranchers brought their cattle in early from the summer range and pledged a thousand dollar reward for the person who killed the bear.
One of them donated an old cow as grizzly bait, and the trapper led the creature into a gulch which he considered suited to his purposes because its banks would help guide the bear to the bait. There he picketed the cow and began rigging his surprise for the bear. When all was in readiness, the old cow stood tethered on a short rope, and surrounding her were three spring guns, each pointing down a potential bear approach route. “The strings to these guns,” Mills recorded, “were silk line stretched over bushes and tall grass so as to be inconspicuous.” In addition, the trapper set four heavy bear traps around the bait in case the bear should slip past the artillery.
The first night, as Mills and the trapper set up their camp and waited, a light snow fell. When morning came they went to the gulch, and there stood the gaunt old cow. Waiting. There was no bear track anywhere around.
When the trapper returned the next morning, however, a line of tracks showed that the grizzly had picked up the scent from a mild distant and come in a straight line to the tethered cow. What he did next was written in the snow for Mills and the trapper to read. The bear halted within two feet of the silk line. He would not touch it. Instead, he followed it around the cow without finding the end to the string.
If the record of what the bear then did had not been written in the snow, Mills might not have believed it. “He then leaped the line,” Mills said, “something I had never before heard of a bear doing.” In approaching the cow the bear managed to avoid each of the traps as if he carried a map of their locations. Moving in between a trap in front of the cow's head and one at her side, he killed the cow, then fed on her where she fell.
When finished with his meal, the grizzly dragged the carcass across two of the traps, springing them, turned and leaped back across the line and departed down the booby-trapped gulch without suffering a scratch.
The trapper, knowledgeable about bears, sensed victory. Now the pattern was set. The bear had claimed his kill and when hunger awakened within him again, the location would be fresh in him memory and the trip from his day bed would be a short one. In the precise spot where the bear landed as he jumped over the silk line, the trapper set still another heavy metal trap. Then he added a fourth spring-gun set to the arsenal, installing this one somewhat below the bait, and stretched the string across the bear's path.
That night, just as the trapper predicted, the bear returned. But instead of coming up the gulch as he had the first night, he approached from above. He retraced his earlier steps around the lines. Something alerted him at the site of his first crossing where the new trap now waited, so he crossed instead at another point where there was no trap.
Still, avoiding all the traps, the grizzly ate his fill, covered the remaining meat with some dead logs, and leaped back over the set lines, and vanished into the night, well fed. Instead of going out by the way he entered, he started down the gulch, a route that would bring him into contact with the new spring-gun set. But he stopped while still a dozen feet from the line, and one can imagine the erect form of the great bear standing there, head up, sniffing the night air for clues.
Instead of advancing, the bear turned and followed the string until he came to the cocked gun waiting at the side of the gulch. Then he simply walked around the rifle and plodded on into the night.
To be outwitted by a bear was more than the trapper could stand, and he renewed his vow to take this animal and claim the reward. Convinced that the grizzly would return, he spent a good part of the next day building a log pen around the remaining bait. The back of the pen was a giant boulder. At the entrance of the pen he set two traps, one inside and one outside. The spring guns remained in position.
The trapper was correct; the grizzly did come back. By this time he knew the drill. He returned with his usual caution, and leaped the string with his usual agility. But at this point he was frustrated. At the single entrance of the pen he apparently once more detected the presence of the hidden traps that guarded the door. His response was to climb to the top of the boulder and, reaching down into the pen, drag up the bait so he could eat.
In doing this, he brushed off one of the pen's top poles. The pole rolled sideways, then fell, crossing a string and firing a rifle. The shot was a complete miss. Who would have thought to aim the rifle at the top of the boulder?
As nearly as Mills and the trapper could reconstruct the bear's reaction to the shot, the animal paused in its feeding and, leaving the meat, climbed down from the boulder. He went to the smoking gun and inspected it.
He then returned to his meal, dragged the bait from the boulder to the ground, and cleaned the remaining bones of all their meat. No longer was there food here for him to protect, and the bear made no effort to cover the bones. He crossed the line leading to the gun that had fired by his stepping over where the fallen log held it down. He then went up the gully, instead of down, and left the trapper with nothing but the story to show for his days of work.

Due to the post length limit, I must again double post to add the rest...

ursusarctos

 

And the rest in this post is from Learning to Talk Bear, by Roland Creek:

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After six years trodding some of the wildest land in the northern Rocky Mountains, I had yet to see a grizzly bear during the hunting season. Put a rifle in my hand and Ursus arctos horribilisp turned as scarce as Hottentots before a slaver's whip. When I was without a weapon, it seemed I had to kick wildlife-all wildlife-out of the way.

And these are some portions of a section talking about the Mud Lake Bear (once on the internet I saw something referring to this Grizzly as the "Mud Creek Bear", so it may have had several different names):

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The camera lay upon the ground, dented with tooth marks. Part of the frame was missing where the bear had ripped open and sprung the door, its film cartridge gone. The carefully prepared “set” was vandalized: the logs and rocks overturned, brush flattened, snares tripped. The bait-a road-killed deer carcass hung in a a tree-was gone. The Mud Lake Bear had struck again.
“It's his modus operandi,” Rick Mace said as he handed me the camera, a compact Olympus Infinity stamped No. 12. “He usually appears at night and always rips up our trap site.”
I turned the camera over and over, staring at the tooth marks. Johannes Brahms could not have tuned into a Beethoven symphony with more rapt attention than I honed into Mace's sonata.
“We suspected the Mud Lake Bear, of course, but can you believe it? We found the film cartridge off to one side, smashed, but we were able to develop enough film for a positive I.D.”
Mace gets paid for trapping and monitoring grizzly...

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...In the spring of 1987, about the time when Riley's proposed study got off the ground, the coming four-year-old lost his collar. And it wasn't until the following spring, as veteran biologists (who learned grizzly trapping via Chuck Jonkel's Border Grizzly Project) swarmed into the area, that the now nearly grown, unusually dark-colored grizzly was captured again.
It was a near-thing. The process used a cubby set, a pile of logs stacked into a V-shape. The bait is laid inside the tip of the V and a snare is placed in front. The dark-colored male was held by just four toes...

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...Biologists snared the Mud Lake Bear for the last time in June of 1989. This time the mature bruin blundered into a blind trail set. It completed his education, a doctorate in trap distaste. He began writing his thesis within the month...

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Biologists wheeled a culvert trap into position near the woods and baited it with their ripest road-killed deer. During the night, the Mud Lake Bear tripped the trap's gate without entering. Again the device was set. The following night the bear turned over not only the heavy culvert, but it's trailer, too, making no attempt to retrieve the bait. Again, the trap was set. On the third night, Number 146 pushed the awkward contrivance through two barbed-wire fences and, tiring of the sport, decamped for the Swan Range's high country.

First of all, as a comment, the Mud Lake Bear's number is 146...
Second of all, the fact that this Bear is doing this not for food, but simply out of spite, though technically a waste of energy, definitely signifies intelligence.

The book then goes on to explain that their was a viscous fight involving Number 144 and the Mud Lake Bear, in the middle of which, the Mud Lake Bear lost his collar, and a terrier lost it's life (“was all ripped up”)....the loss of the Mud Lake Bear's collar means they have to re-catch him in order to give him a new collar so that they can monitor his movements, etc, and study him, which is important due to both his being the dominant Grizzly of the area, and also already is showing some interesting behaviors...

Before I go on with the quotes, a section that I skipped which contains six recovered pictures from one of his raids, as well as comments for each (though, because I don't have a scanner, I can't actually scan it...and can only post the comments):

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1. Mud Lake Bear Sniffs blood dripping from the bait (road killed deer).
2. Looks up, spots bait. Bear has already triggered surrounding snares.
3. Ambles over to see if this is the right trap station? Yep, number 85. (Note the yardstick enabling biologists to estimate size from remote photos).
4. Returns to try for bait.
5. Becoming angry! Night has fallen. Final two photos are flash lighted.
6. Success! Note rope securing bait in corner (upper left) of all photos in sequence.

As you can see from this its basic procedure is probably arrive, trigger all the snares, and then steel (or not) the bait...

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We flag-hang orange flagging ribbon-on our way from a baited set so we can follow the trail when we return to check it,” said biologist Tim Manley, then a Study trapper. “We could always tell when the Mud Lake Bear was there ahead of us. Every piece of flagging ribbon was down. We put up plastic signs, too, warning people away from the sets. And those signs would be ripped down. He'd invariably trigger our snares, steal the bait, knock over the remote cameras, and generally tear up the site.
Shawn Riley claimed the Mud Lake Bear “ate cameras.” And if the Olympus that Rick Mace showed me was any indication, it certainly appeared so.
“It was his standard operating procedure,” Mace said, “to come to a set during the night and tear it up. He always left a trashed trap site as his calling card.”
All through the rest of the 1990 and 1991, biologists returned to their carefully planned and constructed sets to find them ripped asunder, the bait stolen. When 1992's spring and summer trapping season opened with the same result's, Mace turned his men loose on their nemesis.
“I told them their number one priority was to catch that bear. I said the Mud Lake Bear could tell us a lot about bear behavior and use of the area-if only we could put a collar on him. But he was too smart. He wouldn't just avoid a set, he'd destroy it. Then we'd have to start all over planning the set and laying it out.”
“And you never caught him?”
The project leader shook his head. “We never caught him. We'd make a cubby set and put other snares around it. When he trashed them, we began making trail sets leading to our bait. At one time we had twenty-two snares set around one bait that was hanging from a center tree. And Number 146 triggered every single snare and got the bait anyway.”
When I shook my head in disbelief, Mace said, “Roland, it looked to us like he picked up rocks and limbs in his mouth and dropped them on the triggers. Sometimes he pushed a sapling into a snare to spring it. However he did it, he tripped all twenty-two snares, then took the bait at his leisure.” The man shook his head again and repeated, “We never did get him.”
“So how about this year?” I asked.
The answer was subdued. “He's not out there.”
As of September, the Mud Lake Bear hadn't destroyed one 1993 set. Neither did the study team have a heat-sensor triggered photograph of an unusually dark-colored grizzly taken by remote cameras. For study purposes, Mace at last declared the Mud Lake Bear “dead.”...

A rather sad ending to this great Bear, but, I felt obligated to add it...for those of you who are to lazy to do the math, he died at the age of 10, as still the dominant male of the area (or, quite likely, up until shortly before his death, which may have been caused by a fight); however, it is likely the cause of his death will never be found for certain...or even real concrete evidence for it at all.

This is the best thing I could think of adding that may be new; I'm sure most people here would be familiar with many of their other aspects, such as their strength, etc, specially as much on these things was already posted in this topic, and I doubt their is all that much more I could post, other then this extremely interesting site, which has a lot of extremely interesting info in it.
Some interesting things to note is the growth curve of the Brownies, specially if you look at the male's and consider the fact that the typical male may only live to 12 years of age. Another interesting this is the cub mortallity, which shows that their is little, if any, correlation between whether or not a population is hunted and and their mortallity caused by intraspecific killings...despite the popular beleif that shooting the males lowers this (it is more likely to actually raise it, however, as the article states, due to the fact that then other Brownies would move into the old Brownie's old personal area, and kill the young of that Brownie; young it itself wouldn't actually kill due to being their father).
Also, by the sex ratio chart, you can see that intraspecific killing in fights between males seems to be a rather frequent considering the massive difference (which surely isn't caused by hunting, as not that many are hunter each year; a maximum of only 3% can be hunter per year without seriously damaging population...and one of the non-hunted regions also has a large difference). The reason Yellowstone's difference (46% male :54% female) is probably due to the fact that the population is still expanding and growing, meaning the males aren't forced into conflict, and, the fact that the other non-hunted population is also probably a recovering one, it's is also lower, whereas the hunted populations are probably healthy, which may be why the difference is so ectreme in a few of them, as, for example, in the Alaskan Peninsulas which have very healthy Brownie populations, only 15% of adult Brownies are male, while 85% are female...However, you'll notive probably from scrolling down a little after looking at that chart that the vast majority of Brownies from this region that die do so because of hunters :-[ >:(, meaning the effects of intraspecfic killings may not be all that great here (about twice as many males are killed by hunters as females).

Eh, w/e, that .pdf file should be a very interesting read for anyone interested in Brownies.

taipan

 

This is one of the more interesting accounts of Brown bears I have read. It kind of illustrates the bears strength - but also the strength of bison.
Its an account of a female grizzly attacking a young bull bison observed by TRAVIS WYMAN, Bear Management Office, at Yellowstone -

"I observed the incident from the road on the west sideof the Yellowstone River near the outlet of YellowstoneLake (elevation 2,371 m) on the morning of 23 September2000. I was observing a grizzly bear with 2 cubs-ofthe-year that were digging for pocket gophers (Thomomystalpoides) in a meadow 300–400 m from the Lake Lodge.This family group had been frequenting the area throughoutthe summer. At approximately 1200 hours, the bearsbegan walking northeast along the shore of Yellowstone Lake toward the Yellowstone River outlet at Fishing Bridge. At approximately 1300, the bears emerged onto the road at Fishing Bridge Junction and crossed to the north side. The bears continued walking north in a direction that would have taken them past a young adult bull bison lying under a tree 15 meters from the road. The bison stood up abruptly when the bears were approximately 5 meters away. When the bison stood up, the bears appeared startled. The adult female, then the cubs, stood up on their hind legs and looked at the bison. The bison stood in an alert posture with his tail raised and head down.
After a few seconds, the adult bear lunged toward the bison.
The bison immediately turned away and began trotting east, up slope along a bench directly above the road heading toward Fishing Bridge. The adult bear loped after the bison at less than full speed.
I drove east along the road, observing the movement of the bears and bison approximately 15 meters away. After trotting about 50 m, the bison broke into a full run. The adult bear then chased the bison at full speed. At the crest of the hill above the Yellowstone River, the bear swiped its paw across the hindquarters of the bison, knocking the bison’s back legs out from under it. The bison began to slide down the steep embankment of the hill on its back. After striking a tree with considerable force on its front quarters, the inverted bison continued to slide toward a pedestrian boardwalk at the base of the hill. The grizzly leaped onto the stomach of the inverted bison and skidded down the hill on top of it while attempting to bite at the bison’s neck. The bear and bison came to a stop at the base of the hill on the pedestrian boardwalk. The bear continued to bite and pull at the bison’s neck while the bison tried to get to its feet. The bison managed to stand and struggled to remain standing, but the bear continued to pull the bison back down to the ground. When the bison did stand, its hind legs buckled under its own weight. The bear took advantage of this and jumped onto the back of the bison, biting and clawing at its back, inflicting a number of bite and claw wounds around the bison’s hump and lower back. With a quick head motion, the bull managed to free itself from the bear and stand up a second time. At this time, I observed that the bison’s left front leg was broken. This injury may have occurred when the bison slammed into the tree while sliding down the steep hill. The bison continued attempts to stand and fought off the bear with its head and horns for several minutes. The bear stood up on its hind legs and swiped at the bull’s head with its paws. The bison reacted by rearing up, which caused it to slide backward into a ditch adjacent to the Fishing Bridge boardwalk. Being in the ditch appeared to put the bison in a better position to fend off the bear with its head and horns.
At this time the 2 cubs, which had been observing their mother from on top of the hill, came down and reunited with her near the bison. The bison continued to struggle to keep up-right and bled profusely from its back and hindquarters. The adult bear attacked the bison several more times, but the bison was able to use its head and horns to repel the attacks. The cubs did not participate in these attacks but remained nearby. On 5 occasions the bears left the area and were no longer visible to me, then came back and the adult attacked the bull again, but was unable to kill it. The interval between attacks increased from approximately 5 minutes to several hours between return visits.
At approximately 1800 the bears left and did not return, enabling me to investigate the bison in the ditch. The bison was startled upon my approach and attempted to climb out of the ditch. It fell down and was unable to pull itself out of the mud. Due to the proximity of the bison to the main road and concerns for the safety of visitors and a construction crew working on the road bridge adjacent to the attack site, park management decided to dispatch the bison and move the carcass. After shooting the bison, the carcass was moved 0.9 km away to a location remote from public use areas. Managers hoped that the bear family group would follow the scent trail to where the carcass was disposed and scavenge the remains."

http://www.nrmsc.usgs.gov/products/Predation_Papers.pdf

Shame it wasn't caught on camera!

darkhyena

 

Following the thread on European wolves, I find that bears of the same region suffer from the same unfair apathy.

The brown bears of Europe are the source of all our major folklore and mythology on the species, and yet I find that bears of North America are getting special treatment as the definitive kind.

It was the brown bears of Europe that fought gladiators and lions in the colloseum, that were worshiped and emulated by Viking beserkers, that represented the coat of arms of King Arthur, that took part in bear baiting games in the courts of kings, that became an integral part of Russian folklore etc. The list goes on, and yet I find them to be insultingly overlooked.

It is believed that Ursus arctos colonized America from Asia. Not surprisingly, brown bears of the Old World show much higher diversity in appearance and behavior than their descendants in USA and Canada. It is possible that this species is undergoing further speciation before our very eyes.
http://dinets.travel.ru/russianbears.htm

Surely this is worth SOME interest?


Italian Bears (Orsi)

These bears along with the now extinct Atlas bear fought in Roman arenas against gladiators and lions. They're among the most physically distinct brown bear subspecies, having a golden 'mask'.







Syrian Bears

A beautiful, pale furred subspecies that made a name for itself by battling various heroic shepherds mentioned in the Bible.




Iberian Bears (Osos)








Carpathian Bears (Urs)
This is a secretive, dark furred subspecies reputed to be somewhat more sinister in nature than other European brown bears. Ivan the terrible is said to have used these bears as executioners in his dungeons.

taipan

 

Yellowstone Science Volume 10, Number 4, Fall 2002


Evidence of grizzly bear predation on a black bear in
Hayden Valley


by Kerry A. Gunther and Mark J. Biel

Both grizzly and black bears live in Yellowstone National Park. In this and other areas where grizzly bears and black bears are sympatric (share habitat), temporal isolation and behavioral differences tend to reduce direct competition between the two species. In the Greater Yellowstone Ecosystem, grizzly bears are generally most active from dusk until dawn, while black bears are most active during the daytime. Grizzly bears evolved to forage in open meadow habitats, whereas black bears are primarily adapted to living in forests. Grizzlies also have longer claws and larger shoulder musculature than black bears, making them more efficient at foraging roots and ground dwelling small mammals abundant in open meadows. Grizzlies are generally larger than black bears, and are much more aggressive in defending themselves and their offspring from predators, including other grizzlies. Black bears typically escape predators by running into forest cover or climbing trees.

www.nps.gov/yell/planyourvisit/upload/YS10(2).pdf

On August 2, 1998, park visitors looking for grizzly bears from Grizzly Overlook in Hayden Valley observed some ravens on a carcass on the northeast side of the Yellowstone River. Upon focusing their spotting scope on the carcass, they could clearly see the partially consumed remains of a black bear in the tall grass next to the river. The visitors reported the presence of the carcass to Canyon area rangers, who immediately forwarded the report to the park’s Bear Management Office. We received permission from the rangers to canoe across the Yellowstone River to examine and retrieve the carcass. Accompanied by biological technician Christie Hendrix and park ranger Keith Gad, we canoed across the river to the carcass. Although the dead bear was not visible to motorists along the road, a large number of park visitors immediately pulled over to watch as we launched the canoe, creating a large canoe-jam. We paddled downstream and across the river and pulled the canoe up onto the bank next to the black bear’s carcass to examine it. The carcass was that of an adult male weighing (minus the eaten tissue) 171 pounds. Prior to being consumed, the bear had likely weighed over 200 pounds. The bear had canine puncture wounds to the head and nose, as well as a crushed skull and left eye socket.

The wounds were consistent with those that would have been inflicted by a bear or other large predator. When fighting, bears will often bite each other on the nose in an effort to neutralize their opponents’ weapons (teeth). We also found two bear scats containing vegetation next to the carcass. The predator that had killed and partially consumed the black bear had likely defecated these scats while feeding on its carcass. We collected the scats for DNA analysis to aid in determining the species of the predator that had killed the black bear, then loaded the carcass and two scats into the canoe and ferried upstream back across the river to the large aggregation of people that had congregated to watch. After letting the visitors see the bear, and explaining possible scenarios of what may have happened, we loaded the carcass into our truck, covered it with a tarp, and headed back to Mammoth.



We took the bear’s carcass to Neil Anderson at the Montana Fish, Wildlife and Parks Wildlife Laboratory in Bozeman, Montana, for necropsy. Neil was able to measure one set of canine puncture marks he believed were caused by the lower canines of the
predator that killed the black bear. The center-to-center distance of these canine puncture marks measured 59 mm, too large to have been from an adult wolf, mountain lion, or average sized black bear. Measurements taken from reference skulls show that canine widths in that range are typical of average size, adult male grizzly bears in the GYE, although we could not completely rule out a very large adult male black bear as the predator. The identification of the predator that killed the black bear as a grizzly (based on the canine width of wounds found on the black bear’s head) was later supported through laboratory analysis of DNA extracted from the bear scats collected at the kill site. We sent the scats to Dr. Lisette Waits at the University of Idaho for analysis, and DNA extracted from the scats indicated that they were in fact, from a grizzly bear.



When threatened, black bears typically run to forest cover or climb a tree. In this case, the nearest climbable tree to the site where the black bear was killed was a single dead snag on a small island in the middle of the Yellowstone River over 70 meters away. The nearest climbable live trees were approximately 130 meters away on the opposite shore from the bank where the black bear was killed. The nearest climbable trees that could be reached without swimming were almost 1,000 meters northeast of the kill site. This observation lends insight into what can happen to black bears that wander too far from forest cover in areas occupied by grizzly bears, and why we rarely see black bears in the large, non-forested areas of YNP such as Pelican and Hayden Valleys, where grizzly bears are common.

taipan

 

Salmon Fishing

"The bears are typically solitary animals, but congregate in places where there is an abundant food source. The rich salmon fisheries of the Alaskan Peninsula make for primary brown bear habitat; Katmai is home to one of the densest populations of brown bears in the world, and consequently many of the images we see are taken there. Though Alaskans tend to differentiate the coastal bears from the grizzlies of the interior and Lower 48 States, the 2 are actually the same species, both known as "Ursus arctos horribilis". The rich protein of their salmon diet makes for big bears. Males, known as 'boars' can reach weights of over 1500 pounds and stand over 10' tall. Grizzlies in places like Denali or Wrangell-St. Elias National Park, are rarely half that size, as much of their diet consists of berries, roots and grasses. "

dasyurus

 

Grizzly Bears Feast On Diverse Diet
Sunday 18 February 2007

There's no such thing as picky grizzly bears--they'll eat almost anything they can find. A new University of Alberta study that tracked food habits of the Alberta grizzly bear living in the foothills sheds some light on the animal's varied diet and their activity pattern. "Alberta bears have remarkably diverse diets," said Dr. Mark Boyce, biological sciences professor at the U of A and co-author on the study. "They'll eat just about anything." Ants, fruits, moose and plants are a few staples of the Alberta grizzly bear's diet. This new research study was the most comprehensive examination of grizzly bear foods ever conducted in Canada. Using global positioning system (GPS) radiotelemetry technology and analyzing 665 feces collected from 18 grizzly bears over a period of three years, the scientists found that the bears packed a lot of activity into 24 hours. The research was recently published in the Journal of Mammalogy.

Much is known about what bears in mountainous areas eat but little is known of the diets of grizzly bears living in boreal forests also used by humans. As well, this new research looked at five different activities the bears use to find food--whether it feeds on flowers, insects, fruits, digs for plants or kills other animals, specifically ungulates. The diverse diets of the Alberta grizzly bear helps cushion them against climate change and other vagaries of the environment, said Boyce. Specifically, the research team found that the bears living in the foothills are effective predators on moose and deer. They are especially good at killing moose calves during the difficult spring period when other foods like berries are not yet available, said Boyce. Mountain bears are largely vegetarian, by comparison.

The scientists identified 40 different food items, examining each for seasonal patterns of use and differences among mountain and foothills environments. Digging the root of sweet vetch plants dominated early spring diets, while preying on ungulates--or hooved animals--was greatest during late spring, although the timing varied between foothill and mountain bears. Moose were the most common ungulate eaten by the bear (83 per cent), especially newborns (54 per cent), with white-tailed and mule deer (16 per cent) and elk (1 per cent) more minor in comparison. Rodents, insects (primarily ants), and birds were also consumed. Green vegetation dominated early summer diets and as fruit ripened in early August, berries such as soopolallie and mountain huckleberry were added to the bears' menu. The scientists also learned that most of the activity of the east slopes bears takes place in the daytime, especially morning and the evening. This is in contrast to bears living in spots where more frequent contact with humans take place, such as Banff National Park where most bear activity has become nocturnal.

Although the bears are filling up on these different food sources, being so near to highways and roads is dangerous for the animals. "Bears are eating substantial amounts of clover and alfalfa, which are common roadside plantings," said Boyce. "Because these roadside plantings are attractive to bears, this can put the bears at risk of contact with humans. Nearly all new roads being constructed in the province are built by industry, either for timber harvest or oil and gas development. "We should encourage industry to avoid using such attractive food items when planting in ditches and roadsides. It would be much better to use native grasses and other native plants to stabilize road banks and ditches. Most bear deaths occur near roads and we want to avoid attracting bears to areas near roads."

http://www.sciencedaily.com/releases/2007/02/070215083202.htm

pterodectyle

 

Food Habits

Food gathering is a top priority in the life of grizzly/brown bears. They feed extensively on both vegetation and animal matter. Their claws and front leg muscles are remarkably well adapted to digging for roots, tubers, and corms. They may also dig to capture ground squirrels, marmots, and pocket gophers. Brown bears are strongly attracted to succulent forbs, sedges, and grasses. In spring and early summer they may ingest up to 90 pounds (40 kg) of this high-protein forage per day. Bears gain their fat reserves to endure the 5- to 7-month denning period by feeding on high-energy mast (berries, pine nuts) or salmon. The 2 1/2- to 3-month summer feeding period is particularly crucial for reaching maximum body frame and preparing for the breeding season and winter.

Being ultimate opportunists, brown bears feed on many other food items. For example, the Yellowstone grizzlies have clearly become more predatory since the closure of the garbage dumps in the Yellowstone area. They are exploiting the abundant elk and bison populations that have built up within the park. They hunt the elk calves in the spring, and some bears learn to hunt adult elk, moose, and even bison. The ungulate herds, domestic sheep, and cows also provide an abundant carrion supply each spring—the animals that die over winter thaw out just when the bears need a rich food source.

Bears are adept at securing food from human sources such as garbage dumps, dumpsters, trash cans, restaurants, orchards, and bee yards. Some bears learn to prey on livestock, especially sheep that graze on open, remote rangeland.

http://www.extension.org/pages/Grizzly_and_Brown_Bears

taipan

 

Iconic park's grizzlies will feel the heat
By JOEL CONNELLY
P-I COLUMNIST

YELLOWSTONE NATIONAL PARK, Wyo. -- A mother grizzly bear rooted for food as her two cubs romped in a meadow, while we looked through spotting scopes at what's likely the world's most protected habitat.

Antelope Creek, on the north shoulder of Mount Washburn, is closed to human visitors. The world's first, most famous national park extends 20 or more miles in all directions.

Nearby, however, orange and gray whitebark pine trees -- the dying and the dead -- signal a threat to the 500 to 700 grizzlies that inhabit the greater Yellowstone ecosystem.

The cause of the unexpected, fast-emerging peril is global warming.

Grizzlies are great carnivores, but they have a varied diet. Elk and bison calves, and dead elk carcasses, feed Ursus horribilis when it emerges from dens in early spring.

But fat-rich seeds from the whitebark pine, plus thousands of army cutworm moths, build up the bears' weight in the fall and provide calories to live through the winter.

"Will today's cubs, if they live 20 years, still have this food source?" asked Steven Running, a University of Montana ecology professor and group co-chairman of the National Center for Atmospheric Research.

In Alaska and British Columbia, grizzlies scoop salmon out of rivers. Grizzlies in the Northern Rockies have alternative food sources such as fruit from shrubs.

Here, however, seedpods from the whitebark pine "are arguably the most important fattening food available to grizzly bears during late summer and fall," according to the government's Interagency Grizzly Bear Study Team.

"The whitebark pine is on its way out: Whitebark is not going to make it without management intervention," said Diana Tomback, a professor of biology at the University of Colorado and head of the Whitebark Pine Ecosystem Foundation.

The prime threat is a tiny beetle that has lately exploded in population.

The mountain pine beetle has killed 27 million acres of British Columbia's lodgepole pine forest. It has crossed the Continental Divide and threatens to eat its way through to the East Coast. In Montana, it has already killed at least 1.2 million acres of forest.

"It is like a 1988 fire that doesn't go out," said Jesse Logan, a recently retired U.S. Forest Service research entomologist, alluding to the forest fires that raged across Yellowstone.

An outdoorsman, and author of more than 150 scientific articles, Logan loves the beauty of the whitebark pine. The gnarled trees grow at high elevation, near timberline, where other trees cannot. Logan has found trees that are 1,400 years old.

The beetles have been around a long time, too. They are "the number one economic pest in North America," in the words of Diana Six, a University of Montana associate professor of forest entomology and pathology.

Severe winters in the past kept beetle populations under control. Not recently: Rising temperatures have produced increased reproduction.

"What controlled them was when it got down to minus 40 Fahrenheit for a couple of days," Logan explained.

"And we're not getting that anymore," Six added. "Warmer temperatures allow the mountain pine beetle to be successful at higher elevations, and switch to a one-year life cycle."

Logan has a research plot at 10,000 feet elevation in Idaho's White Cloud Mountains. The first sign of mountain pine beetles was detected in 2001. Within two years, virtually all the mature whitebark pines were dead.

"It is amazing how fast this is happening," Logan said. The beetle has spread to Yellowstone's high places: 10,500-foot Avalanche Peak is red from beetle kill. Official figures say 16 percent of whitebark pine in greater Yellowstone has experienced "some level of mortality."

As scientists scramble mountainsides to watch whitebark pines die, the federal government has taken a surprising step: The U.S. Fish and Wildlife Service recently moved to "delist" grizzlies, easing Endangered Species Act protection.

Grizzlies will continue under full protection in a 9,000-square-mile "prime" area that includes the national park. Elsewhere, often-hostile state officials will be free to open hunting season and declare free-fire zones where grizzlies are unwanted.

The Natural Resources Defense Council has filed a lawsuit to stop the delisting. It cites the "decline of key food sources" as reason to continue full protection of grizzlies.

"Just like their polar bear relatives in the Arctic, Yellowstone grizzlies are rapidly losing habitat as a result of global warming," the NRDC argues in its brief.

Logan, Running, Six and Tomback came together last weekend, at a conference sponsored by the NRDC and compared research findings. The scientists hiked to a research plot maintained by Tomback and later inspected beetle kill extending well above 10,000 feet.

The Fish and Wildlife Service didn't talk to any of these people when it decided on delisting.

Logan produced a map showing that whitebark pine is most likely to survive in Wyoming's high Wind River Range, outside the politically drawn boundaries of the "prime protection area."

If bears try to migrate there, for food and refuge, they'll find that locals in Fremont County have officially classified grizzlies as "an unacceptable species."

And that translates to a less technical term: Lock and load.

http://seattlepi.nwsource.com/connelly/324071_joel18.html[/quote]

Edited by Taipan, Oct 24 2017, 11:31 AM.

taipan

 

Size & Weight variance by location & gender

"SUMMARY: The size and weight varies considerably between populations. In most populations, the weight range for males is probably about 135 - 545 kg ( 300 - 1,200 lb) averaging about 200 kg (450 lb) but some individuals may reach 725 kg (1,600 lb); for females, the average is about 135 kg (300 lb) with some individuals reaching 280 kg (600 lb). However, in some populations in southern Europe, average weight is as low as 70 kg and in Jasper National Park, Alberta, averages were 92 kg for males, 55 kg for females. The variation may be due to both genetic factors and nutrition.

• 
  
• Males average larger than females, in a given population.
  
• Males average larger and heavier than females.
  
• 150 - 780 kg (330 - 1,716 lb).
  
• 147 - 680 kg (324 - 499 lb) but with some individuals up to 700 kg (1,700 lb).
  
• Variable, 80 to more than 600 kg.
  

Size varies through the brown bear's range:

• 
  
• In southern Alaska and islands (e.g. Kodiak Island, Admiralty Island), these bears may reach 780 kg.
  
• In Yellowstone in one study, 102 - 324 kg, average 181 kg.
  
• In Europe males may reach to about 200 kg.
  
• In Northern Europe and Siberia usually about 150 - 250 kg.
  
• In southern Europe, 70 kg.
  
• The largest brown bears are those with fish or meat in their diets.
  
• In Europe, up to 200 kg
  
• The heaviest individuals are found in coastal Alaska. In Eurasia, weight increases from west to east with the largest found in coastal Siberia and Kamchatka.
  
• Ursus arctos middendorffi - Alaskan brown bear usually reaches 360 - 545 kg by eight or nine years old and may reach 770 kg (1,700) lb.
  
• Individuals of 1,670 lb (for a Kodiak bear in a zoo) and 1,656 lb for another male Ursus arctos middendorffi from Kodiak Island have been recorded.
  
• In Russia, males may reach up to 400 kg (880 lb).
  
• Bears gain weight considerably in the autumn, putting on fat before hibernation.
  
• Size variations may be partly due to genetics but nutrition is involved since bears from small populations raised in zoos may get quite large.
  

Males:

• 
  
• 135 - 545 kg (300 - 1,200 lb), rarely up to 725 kg (1,600 lb). (
  
• In southwest Yukon, males 139 kg.
  
• The heaviest individuals are found in coastal Alaska: mean 389 kg; on islands (e.g. Kodiak) mean 312 kg.
  
• Siberia males 140 - 320 kg.
  
• Interior Alaska mean 243 kg.
  
• West Brooks Range, Alaska, mean 155 kg.
  
• Yellowstone National Park, Wyoming, mean 193 kg.
  
• Interior of British Columbia, mean 117 kg.
  
• Jasper National Park, Alberta, mean 92 kg.
  
• Northern Yukon, mean 140 kg.
  
• Northwestern Mackenzie, Northwest Territories, mean 159 kg.
  
• Average about 200 kg (450 lb) and maximum usually up to 500 kg (1,100 lb).
  

Females:

• 
  
• Average about 135 kg (300 lb), and maximum usually up to 280 kg (600 lb).
  
• Females may lose 40% of their body weight over winter while hibernating and producing and feeding cubs.
  
• In southwest Yukon, 95 kg.
  
• The heaviest individuals are found in coastal Alaska: mean 207 kg; on islands (such as Kodiak) mean 202 kg.
  
• Siberia females 100 - 200 kg.
  
• Interior Alaska mean 117 kg.
  
• West Brooks Range, Alaska, mean 112 kg.
  
• Yellowstone National Park, Wyoming, mean 135 kg.
  
• Interior of British Columbia, mean 58 kg.
  
• Jasper National Park, Alberta, mean 55 kg.
  
• Northern Yukon, mean 83 kg.
  
• Northwestern Mackenzie, Northwest Territories, mean 99 kg.
  

http://wildlife1.wildlifeinformation.org/list_vols/Bears/Ursus_arctos/01Ursus_arctosAMWtHt.html

taipan

 

Why do grizzlies rub against trees?
Study says they mark trees so other bears can get to know them better

By Andrea Thompson

Updated: 8:19 p.m. ET Sept. 5, 2007

Grizzly bears that rub their backs against trees aren’t trying to scratch that unbearable itch. They’re actually doing it to communicate with each other, one scientist says.

Researchers have suggested many theories as to why grizzly bears get cuddly with trees. Some thought females might do it as they became most fertile, while others thought that bears might just be giving their backs a good scratch or trying to cover them in sap to use as insect repellant.

But a new two-year study of grizzlies in British Columbia used digital cameras to collect data on which bears used the trees for rubbing and when (bears use the same rub trees for generations, so it's easy to know which trees to watch). Satellite equipment also helped track the movement of individual bears.

"The cameras show that adult male bears are the most likely to rub trees, and the satellite telemetry tells us that males move from valley to valley in large loops, marking trees as they go, while looking for breeding females," said ecologist Owen Nevin of the University of Cumbria, who conducted the study.

Nevin, who will present his findings at the Sept. 10 annual meeting of the British Ecological Society, thinks that by marking the trees with their scent, the male bears get to know each other better, which could reduce fighting among the bears over female mates.

"Big male bears can seriously injure or even kill each other when they get into a fight," Nevin said. "If one recognizes the other from the scent marks on the rub trees in the area, he knows he's in for a tough fight — he's on the other guy's patch so to speak — so it might be better to back away than make a serious challenge."

Cubs have also been observed rubbing trees when a male is trying to chase them away from their mother (male bears will sometimes kill a female's offspring to get a chance to mate with her).

"They can visit the tree two or three times a day, sometimes within an hour of the big males, so it may be that smelling like him makes them safer — related animals smell similar and animals are less aggressive toward relatives," Nevin said.


A grizzly bear rubs up against a tree to mark his scent, a scientist says.

http://www.msnbc.msn.com/id/20610392/from/RS.1/

scottwolverine1111

 

taipan

 

Surburban Romania rife with 'foraging' bears

By Europe Correspondent Emma Griffiths

Posted Tue Nov 6, 2007 9:09pm AEDT
Updated Tue Nov 6, 2007 9:56pm AEDT


Romania's bear population flourished in Communist times because of a hunting ban. (Reuters: Christian Charisius)
In many parts of Europe wild animals like bears and wolves are making a comeback, and in one country the bear population is flourishing.

There are so many brown bears in Romania that they are a common sight wandering through villages and farms, and in some big towns they have been seen foraging through the suburban bins.

The population boom has led to a debate about how many bears the country's forest can sustain, and it has also fuelled a controversial new business for Romania - hunting tourism.

Another bear and her four cubs are tucking into their dinner. It is not the middle of the forest, or a zoo, it is a suburban street in the Romanian town of Brasov, and the bears' picnic has been provided courtesy of the neighbourhood bins.

The bears have ventured down from the surrounding hills to eat their way through plastic bags of garbage, searching for any tasty morsels discarded by the humans living just across the street.

They have become a tourist attraction, and a source of pride for residents, but for the garbage collectors, cleaning away a bear's meal can be a little tricky.

"They kind of scare us," a garbage man admits, "we chase them away with rocks, we clap and they go up the hill. And they make a mess."

Romania has the largest bear population in Europe. The animals flourished in Communist times because of a hunting ban imposed by the former dictator, Nicolae Ceausescu.

Only he and his cronies were allowed to hunt for bears, and by the time he was ousted in 1989, their numbers had soared.

Current estimates range from 3,000 bears to more than double that.


Bears in trouble

It helps to explain why they are roaming beyond the forests and into towns like Brasov.

Christina Lapis is a wildlife activist who has made it her life's work to protect Romania's bears.

She says they are being pushed out of their habitat, and foraging through the town's garbage is evidence that they are in trouble.

"For the bears in Brasov I should prefer to take them in another place to release them and to let them live free," she said.

"It's very stressful for them, they are coming for food.

"They find here easy food, but for this they pay with their behaviour - now they are used [to it] and they have a different behaviour."

The healthy population of brown bears has spawned a big business in hunting tourism.

The bear hunt is limited to about 300 animals a year, so just as in Communist times, it is an elite practice, only open to those who can pay the fee of several thousand dollars.

Veteran hunter Todor Danitz guides wealthy Western Europeans through the forests to claim their trophies.

"The bear is a rare animal," he said.

"Just like a person desires something that is out of reach, in the same way he wants to shoot a bear, because then others will call him a bear hunter."

The Brasov Hunting Association says there are more than enough bears to sustain the quota. Mr Danitz has even likened it to a controlled cull.

But for conservationists, it is another threat to the animals known as the king of the European forest.

Despite the number of bears, they say they say they have a precarious future, and must be protected.


Romania's bear population flourished in Communist times because of a hunting ban.

http://www.abc.net.au/news/stories/2007/11/06/2083558.htm

dasyurus

 

Bear Hunting Altered Genetics More Than Ice Age Isolation

ScienceDaily (Nov. 26, 2007) — It was not the isolation of the Ice Age that determined the genetic distribution of bears, as has long been thought. This is shown by an international research team led from Uppsala University in Sweden in the latest issue of Molecular Ecology. One possible interpretation is that the hunting of bears by humans and human land use have been crucial factors.

Twenty thousand years ago Europe was covered by ice down to Germany, and the climate in the rest of Europe was such that several species were confined to the southern regions, like the Iberian Peninsula and Italy. These regions were refuges, areas where species could survive during cold periods and then re-colonize central and northern Europe when it got warmer.

But the brown bear was not limited to these regions -- ­it could roam freely across major parts of southern and central Europe. The current study analyzed mitochondria from bear remains. Some of the fossils are 20,000 years old. The analysis shows that the genetic pattern in these ancient brown bears differed from that of bears living today.

“Previously today’s genetic structure was interpreted as showing that the brown bear was isolated in southern Europe, just like many other species. But our study shows that this was not the case,” says Love Dalén, one of the Swedes participating in the study.

The new findings show instead that the brown bear survived in central Europe, even during the coldest period of the Ice Age. The scientists now believe that the genetic pattern found in today’s brown bears is the result of historical hunting and of human activities in the brown bear’s natural environment. A few thousand years ago, there were brown bears all over Europe, while today there are just a few remaining populations in Spain, Italy, the Balkans, and Scandinavia.

“It’s not strange that findings were interpreted differently in the past, with the brown bear extinct in most of its old area of inhabitation. We only had the remnant populations to work with,” says Anders Götherstam, who directed the study.

The study was carried out in collaboration between Swedish researchers and colleagues in Spain, the U.K., Germany, and France. It is published in the journal Molecular Biology. The Swedish team also includes the researcher Cecilia Anderung.

Adapted from materials provided by Uppsala University.


European Brown bear walking in the forests of Finland.

http://www.sciencedaily.com/releases/2007/11/071126115307.htm

taipan

 

^^ Interesting material Frank

Study Of Bear Hair Will Reveal Genetic Diversity Of Yellowstone's Grizzlies

ScienceDaily (Dec. 18, 2007) — Locks of hair from more than 400 grizzly bears are stored at Montana State University, waiting to tell the tale of genetic diversity in the Yellowstone Ecosystem.

Ranging from pale blond to almost black, the hair is filed in a chest freezer where the temperature is minus-77.8 degrees. Some of the tufts are almost 25 years old.

The hair will head to Canada in a few months to be analyzed at Wildlife Genetics International in Nelson, British Columbia, said Chuck Schwartz, head of the Interagency Grizzly Bear Study Team based at MSU. The team is monitoring the genetic diversity of the Yellowstone grizzlies over time and wants to know when new DNA appears. The team will also compare the Yellowstone bears with those in the Northern Continental Divide Ecosystem where a similar study has been done.

"An objective of the study is to determine if bears from the Northern Continental Divide Ecosystem migrate to the Yellowstone," Schwartz said.

The Northern Continental Divide Ecosystem includes Glacier National Park, parts of the Blackfeet and Flathead Indian Reservations, parts of five national forests, five wilderness areas and Bureau of Land Management property in northwest Montana. The Yellowstone Ecosystem includes Yellowstone and Grand Teton National Parks, six national forests, and state and private land in portions of Montana, Wyoming and Idaho.

An estimated 550 to 600 grizzlies live in the Yellowstone Ecosystem, about twice what it was 20 years ago, but the population currently lacks diversity, Schwartz said.

"We know it's low," he said. "There are concerns about inbreeding and other issues because we don't have new genes flowing into the system on a regular basis."

Field crews from a variety of federal and state agencies plucked the hair the study team is storing, Schwartz continued. Each lock came from somewhere off the bears' shoulders, but the way it was collected varied. Some of the bears died of natural causes or were killed by humans. Other bears were temporarily unconscious while scientists fit them with radio collars or moved them to another location after they'd gotten into trouble. Some bears left hair behind while crawling underneath barbed wire.

"The vast majority of the time, it is routine," Mark Haroldson said of the collection process. Haroldson is a supervisory wildlife biologist with the Interagency Grizzly Bear Study Team. He has collected bear hair since the late 1980s.

Schwartz said researchers in Idaho can tell him if the hair came from one bear or several. They can tell him the bear's gender and whether the hair came from a bear at all. To answer the tougher questions, Schwartz turns to the Wildlife Genetics International, which routinely analyzes hair from grizzlies, black bears, wolverines and other wildlife in Canada and the United States. The Canadian lab examined the grizzly hair from the Northern Continental Divide Ecosystem. It also analyzes hair collected by MSU graduate students in Yosemite National Park in California and Banff National Park in Alberta, Canada.

Bear hair is tricky because the amount of DNA it contains is so small, said Steven Kalinowski, the students' adviser and a conservation geneticist in MSU's ecology department. Jennifer Weldon, manager of the Canadian lab, said dirty hair can challenge some researchers. So can hair that came from a dead animal and spent so much time in the elements that the DNA degraded.

Schwartz said shafts of the Yellowstone hair will eventually return to MSU so he can conduct other tests and have samples available when new study techniques are developed.

Adapted from materials provided by Montana State University.


A curious bear investigates the smell of blood near a wire hair snag.

http://www.sciencedaily.com/releases/2007/12/071218134821.htm

taipan

 

Grizzlies have great sniffers

Posted: Wednesday, Aug 03, 2005 - 11:20:16 am MDT
By CHRIS PETERSON

Hungry Horse News

When it comes to grizzly bears, the nose knows - boy does it know.

Dr. George Stevenson, a retired neurosurgeon from Jackson Hole, Wyo. has been examining the brains of grizzly bears for the past year. Within nine months to a year, Stevenson and a team of neuroscience students hope to publish a "rough" atlas of the grizzly bear's brain.

What he's seen to date is fascinating, Stevenson said earlier this week.

For example, a grizzly bear's nose is highly developed - thousands of times more developed than a human's, and far better than the best tracking dog's nose.

"They have the greatest olfactory (mechanism) on earth," Stevenson said.

He said the portion of the grizzly brain that governs smell looks like a golf ball with porcupine quills running out of it.

Those quills are nerve endings that run to another part of the grizzly's brain - the gray matter where memories are stored.

Grizzlies, compared to other animals, have a lot of gray matter, Stevenson notes. That gray matter allows grizzlies to remember where food and shelter and all the other necessities of life are - via smell.

"We're very impressed with the olfactory systems of bears," he said. "I think they smell their way through life."

Stevenson's research corroborates other studies of bears. Grizzlies have been known to travel for miles - sometimes more than hundreds of miles - just to reach a prime berry patch.

Bears are also known for having a knack for finding their way home. Past management bears have been caught from, say, the North Fork of the Flathead, moved a long ways away, only to return within a week.

How do bears find their way?

Smell, Stevenson theorizes. They use smell to remember places. Just like you remember the smell of your mother's pancakes for breakfast, a bear uses smell to remember exact locations of its last good meal. And that meal may have been three years ago with mom on a favorite mountainside in June.

"Olfaction memory is a big thing in grizzly bears," he said.

Stevenson's findings are not necessarily surprising, but they are "fascinating," said Chris Servheen, the grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service.

"No one has ever looked at bears the way (Stevenson) is doing it," Servheen said. "We're lucky to have someone like George doing this."

Servheen said the research, at least now, doesn't have much impact on the way bears are managed, other than giving biologists a better view of the thought process of bears. But who knows? Somewhere down the line it could have management implications.

Stevenson is also looking at the pituitary glands of bears and how it connects with the brain. The pituitary gland is the part of the brain that would control hibernation.

He said it's too early to say for sure the pituitary gland is better developed in bears, but he suspects that it is - at least in some species. Hibernation is a natural biological mechanism that allows bears to have and raise young and save energy through the winter months.

But not all species of bear hibernate, Stevenson notes. Tropical bears for example, don't hibernate. Even some North Fork grizzly bears don't appear to hibernate - or if they do, they don't hibernate for long.

Temperature and the way the bear's brain senses temperature changes may actually start the hibernation process, Stevenson theorized.

Stevenson to date has looked at six different grizzly bear brains. They come from management bears - bears that would be normally euthanized because of management concerns, such as depredation or continual raids on human dwellings or households or bears that are accidentally killed.

No bears are killed for the study.

The study is being completed in cooperation with U.S. Fish and Wildlife Service and Montana Fish, Wildlife and Parks.

http://www.hungryhorsenews.com/articles/2005/08/03/news/news02.txt

admin

 

Campaigners want tribute for WWII 'soldier bear'

Posted 6 hours 38 minutes ago

Scottish campaigners are calling for a memorial to a bear which joined Polish troops on the front line during World War II and later died in Edinburgh, media reported.

Voytek, a 113-kilogram, 1.8-metre brown bear, was adopted by the Poles after they found it in Iran in 1943.

They gave the animal beer and cigarettes, trained it to carry mortar shells and even enlisted it as a soldier so that it could keep travelling with them.

The bear saw action at the battle of Monte Cassino in Italy, where it was credited with bringing up supplies of food and ammunition under heavy bombardment.

At the end of the war, the troops were billeted to southern Scotland and Voytek went along too, before being sent to Edinburgh Zoo when they were demobilised.

The animal remained at the zoo until its death in 1963.

Now a teacher from southern Scotland, Garry Paulin, has written a book about the bear and a campaign has started to have Voytek's life commemorated in a statue.

Campaigner Aileen Orr said she first heard about the bear as a child from her grandfather, a Scottish soldier.

"The story is totally amazing and it would be good if we could have some memorial in Scotland, perhaps at Holyrood (the Scottish Parliament in Edinburgh), to celebrate the bear's life," she told the Scotsman newspaper.

Polish veteran Augustyn Karolewski, who still lives in Scotland, added: "He was like a big dog - no-one was scared of him.

"He liked a cigarette, he liked a bottle of beer - he drank a bottle of beer like any man."

- AFP

http://www.abc.net.au/news/stories/2008/01/27/2147412.htm

More pictures here : http://www.vbservices.co.uk/baczor/html/wojtek.html

admin

 

Some more photos & information on Voytek, the soldier bear.



As for Voytek, he was just happy to be part of the unit... ever ready to lend a helping paw.

The 250lb brown bear, standing more than 6ft tall, was possibly the most remarkable combatant of the Second World War, seeing action amid the hell of Monte Cassino in Italy.

After the war, he and his fellow troops were billeted in Scotland and he lived out his days in Edinburgh Zoo, dying in 1963.

Now a campaign is under way to build a permanent memorial to the remarkable animal who fought so valiantly for the Allied forces.

Voytek was just a tiny bundle of fur when he was discovered wandering in the hills of Iran by the Poles when they were driving towards Palestine in 1943.

Having lost his mother, he attached himself to the men, who fed him on condensed milk and gave him an old washing up bowl to sleep in.

Voytek soon took on many human characteristics, crying when left alone and covering his eyes with his paws if chastised.

As he grew, he became a key member of the unit, being trained to carry mortar shells.

In the heat of summer, he reportedly learned to work the shower of the unit's bath hut.

On one occasion, Voytek was delighted to find the door ajar - and discovered an Arab who was spying for a raiding party.

The intruder confessed all, and the enemy were rounded up. Hailed a hero, Voytek was given two bottles of beer and allowed to spend all morning splashing happily in the bath hut.

When the Poles were deployed to Italy in 1944 to supply Allied troops with desperately-needed food and ammunition, the only way to take their furry friend with them was to officially enlist him - so he was given a name, rank and number.

As the bitter battle for the monastery of Monte Cassino was fought, the bear travelled in the munitions trucks, his head hanging out of the window, ignoring almost constant shellfire.

Cradling 25lb shells or boxes of ammunition in his arms, he would effortlessly pass them down the line. Off-duty, he loved a bottle of beer, a cigarette and to wrestle with the men - in between raids on the cookhouse.

At the end of the war, the transport company was stationed in the village of Hutton, Berwickshire, where Voytek became a local legend.

"He was like a big dog, no one was scared of him," said Polish veteran Augustyn Karolewski, 82, who still lives near the site of the camp.

"He liked a cigarette, he liked a bottle of beer - he drank a bottle of beer like any man." When the troops were demobilised, Voytek moved to Edinburgh Zoo.

Mr Karolewski went to see him and found he still responded to the Polish language.

"As soon as I mentioned his name, he would sit on his backside and shake his head, wanting a cigarette.

"It wasn't easy to throw a cigarette to him - I made several attempts until he got one."

Teacher Garry Paulin has written a book, Voytek - The Soldier Bear, which will be published next month.

Aileen Orr, who lives in Hutton, is campaigning for a memorial. "The story is totally amazing and it would be good if we could have some memorial in Scotland, perhaps at Holyrood, to celebrate the bear's life," she said.


And like any other combatant, he is even said to have had an official name, rank and number.

Now a campaign is underway to build a permanent British memorial to the remarkable bear who fought so valiantly for the Allied forces and lived out his final days in Edinburgh Zoo.

Voytek was just a tiny bundle of fur when he was discovered wandering in the hills of Iran by the Second Polish Transport Company when they were driving through Persia towards Palestine in 1943.

Having lost his mother, he immediately attached himself to the men who fed him on condensed milk and gave him an old washing-up bowl to sleep in.



Voytek soon took on many human characteristics, including crying like a baby whenever his master left him and covering his eyes with his great paws when he was chastised.

Little wonder that the troops adopted him, and soon found he could be a useful addition. As he grew he was trained to carry heavy mortar rounds.

Story has it that in the heat of summer he learned to work the shower, and used it so often that the Nissen hut had to be locked to prevent him exhausting the water supply.

On one occasion, Voytek was delighted to find the door ajar. Entering the bear discovered a cowering Arab who had come to spy out the lie of the land for a raiding party, intending to steal all the weapons and ammunition.

The spy confessed all, the raiding party were rounded up, and Voytek became a hero. He was given two bottles of beer and allowed to spend all morning splashing happily in the bath hut.



When Polish forces were deployed to Europe the only way to take the bear with them was to enlist him.
He was given a name, rank and number and when the Polish II Corps arrived in Italy in 1944 to supply their own and British frontline soldiers with desperately needed ammunition and food, Voytek was their secret weapon.

Despite almost constant heavy fire, Voytek travelled in the munitions trucks, his head hanging out of the window.

He helped the supply side by cradling 25lb shells or boxes of ammunition in his arms and passing them down the line.

Off-duty, he loved nothing more than a bottle of beer, a cigarette and to wrestle with the men - in between raids on the cookhouse.

By the end of the war, Voytek had become a symbol of ursine courage, but his country was under Soviet domination, so he travelled with other Polish troops to Scotland and the Berwickshire village of Hutton.

Soldiers who were stationed with him say that he was easy to get along with.

Polish veteran Augustyn Karolewski, 82, who still lives near the site of the camp in Berwickshire, said: 'He was like a big dog, no-one was scared of him.

"He liked a cigarette, he liked a bottle of beer - he drank a bottle of beer like any man."

When the troops were demobilised, Voytek spent his last days at Edinburgh Zoo, where died in 1963.

Mr Karolewski went back to see him on a couple of occasions and found he still responded to the Polish language.

He explained: "I went to Edinburgh Zoo once or twice when Voytek was there.

"As soon as I mentioned his name he would sit on his backside and shake his head wanting a cigarette. "It wasn't easy to throw a cigarette to him - all the attempts I made until he eventually got one."

Teacher Garry Paulin has written a book Voytek -The Soldier Bear, which will be published next month. Campaigner Aileen Orr, who lives in the village of Hutton, said she first heard about Voytek as a child from her grandfather who served with the King's Own Scottish Borderers.

She said: "I thought he had made it up to be quite honest but it was only when I got married and came here that I knew in fact he was here, Voytek was here.

"It is just amazing, the story is totally amazing and it would be good if we could have some memorial in Scotland, perhaps at Holyrood, to celebrate the bear's life."

taipan

 

Grizzly found in polar bear country
High-Arctic sighting more evidence of population's spread northward

Ed Struzik, The Edmonton Journal
Published: 7:15 am

EDMONTON - Charles Francis was flying across Melville Island in the High Arctic conducting a shorebird survey with two other biologists last summer when they spotted what they thought was a polar bear feeding on a muskox.

This, however, was one dirty looking bear, according to the Canadian Wildlife Service scientist.

"Initially, we thought that this might have been a hybrid like the grizzly bear- polar bear cross that had been shot in the Arctic a couple of years earlier.

"But when we got back to camp and had a good look at the pictures I had taken from the back window of the helicopter, we realized that this was a very healthy grizzly."

Normally, grizzlies don't stray further north than the Arctic coast of Canada and Alaska where a good part of their traditional food supply -- berries, ground squirrels, and barren ground caribou -- is found.

But in recent years, there have been more and more sightings of the animals ranging on the sea ice north of the mainland and as far north as Banks Island.

Back in 1991, one was spotted on the sea ice north of Banks and south of Melville hunting seals. Following the tracks of that animal, the scientist in pursuit discovered that the bear had fought and won a battle with a polar bear doing the same thing.

No one was quite sure what aklark, the Inuit name for the grizzly bear, was doing up to in the kingdom of nanuk, the word they use for polar bear.

But when American hunter Jim Martell shot and killed that grizzly-polar bear cross more than two years ago, many scientists started to wonder if the northward march of the barren ground animal was more than the oddity than it was once considered to be.

The Melville bear now has scientists scratching their heads again.

Not only has this bear gone further north than any other grizzly is known to have gone in North America, the evidence suggests he's been there for three years.

That's how long it's been since University of Alberta geographer John England spotted a grizzly on the same island. England is convinced it's the same animal.

Andrew Derocher is in the midst of a long-term study of barren ground grizzlies in the Arctic.

The University of Alberta scientist speculates that this bear got to where he is today not by swimming across the Arctic Ocean, but by walking over the ice.

"The bear might have been in pursuit of caribou from the Dolphin-Union herd that cross the sea ice from the mainland in spring," he says.

"He may also have been wandering far from shore hunting seals like its white cousin. Alternatively, it could have been dispersing from where it was born and chose north rather than another heading."

Derocher isn't surprised that this bear, which appears to be a male, is in such good shape.

"These bears are very resourceful and able to make do with little," he says. "What is it eating? Dead caribou, dead muskox, calves of muskox and caribou, hunter kills, polar bear kill leftovers, berries, bird eggs, fish, marine mammal carrion. There are no ground squirrels, but lemmings would make some fine grub. I recently heard of a bear in northern Alaska that spent an entire summer eating lemming. Killing muskox is also pretty standard for barren ground grizzlies."

While it's just a guess, Derocher speculates that this animal is getting some marine protein from seals and whales. "And given the fact he may be rather 'lonely' with no females about, this bear is likely not using much energy mating or fighting other males," he adds.

No one knows if this northward migration represents a trend.

Warmer weather, longer summers and new and better harvest management appear to have resulted in an increase of barren ground grizzlies along the northern coast of Canada.

Those younger males that are the dispersing segment of the population, explains Derocher, are often forced to venture into new frontiers. (Young females are allowed to remain near their mothers and set up, but males are kicked out and pushed into territory that is already occupied by other more mature males.)

Emerging hungry from its den when there is still snow covering the ground in spring, it wouldn't take much to compel a young bear to follow a herd of caribou across the sea ice, says Derocher.

"But then maybe, it just had to leave home and north seemed as good an option as south."

estruzik@thejournal.canwest.com

http://www.canada.com/edmontonjournal/story.html?id=ad85f5d7-4700-49a8-8767-334ee5c4d760&k=63469&p=1

taipan

 

Saving Spanish Brown Bears With Help From European Bears Might Make Sense

ScienceDaily (Mar. 19, 2008) — Brown bears from the Iberian Peninsula are not as genetically different from other brown bears in Europe as was previously thought. An international study being published in Proceedings of the National Academy of Sciences, shows that, to the contrary, the Spanish bear was only recently isolated from other European strains. These findings shed new light on the discussion of how to save the population of Spanish bears.

The researchers extracted DNA and determined the gene sequence of bears from prehistoric material, primarily from the Iberian Peninsula. Some of the material was as much as 80,000 years old. When the data material was analyzed, what emerged was a totally unexpected pattern.

"We expected to be able to follow the Spanish brown bear far back in time, but we found to our amazement that it had genetic material from bears in other parts of Europe. In fact, it seems that the Spanish bear was isolated for the first time in our own time," says doctoral student Cristina Valdiosera, who performed most of the laboratory and analytical work.

"These bears have possibly been isolated in Spain for a few thousand years, which is a very short period in an evolutionary perspective. In other words, there has been a flow of genes to and from the Iberian Peninsula throughout most of the time brown bears have been there. This is extremely interesting data when we discuss transporting bears from other areas to Spain for the purpose of preservation," says Anders Götherstam, who directed the study.

The number of bears on the Iberian Peninsula is limited, with the population divided into two small groups in the north. In-breeding and genetic depletion constitutes a serious threat to the bears' survival in this area. For preservation purposes, the possibility of introducing bears from other areas to the Iberian Peninsula has been discussed, but it has been argued that this would entail the extinction of the genetically unique Iberian bear. It has also been feared that bears from other areas are not as well adapted to the living conditions on the Iberian Peninsula as the Spanish bears are.

"But since there has never been a genetically isolated brown bear on the Iberian Peninsula until very recently, these arguments can be questioned," says Anders Götherstam.

The study was performed collaboratively by scientists from Spain, France, Germany, the UK, and Sweden.


A new study shows that the Spanish bear was only recently isolated from other European strains.

Adapted from materials provided by Uppsala University.

http://www.sciencedaily.com/releases/2008/03/080318094519.htm

taipan

 

Hibernating grizzlies emerge early from dens

Cathy Ellis, For the Calgary Herald
Published: Saturday, April 12, 2008

American scientists are hoping to determine if climate change is causing grizzly bears to hibernate later each fall and emerge from their winter slumber much earlier.

It's a trend that has been noticed on both sides of the border.

Researchers in the Greater Yellowstone ecosystem want to know if shifting weather patterns may be influencing the denning behaviour of some of the area's 500 to 600 grizzlies.


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Font:****Their findings, based on data collected from 1975 to 1999, show radio-collared adult males heading into their dens later each year. They have noticed a corresponding trend of higher overnight temperatures each November.

"We've got some correlations with temperature and snowfall to suggest they're probably staying out later in the fall," said renowned U.S. grizzly bear expert Chuck Schwartz.

"It appears they are also coming out a bit earlier in the spring as well. There is some timing associated with them coming out earlier, though, because it doesn't behoove a bear to come out of a den before food is available."

The Greater Yellowstone ecosystem covers an area of about 37,500 square kilometres, including Yellowstone and Grand Teton national parks and surrounding national forest lands.

Closer to home, researchers in Banff National Park have also noted some large male grizzlies are spending less time in their dens over the winter.

Schwartz said grizzly bears are exposed to a greater chance of conflict with humans if they remain out of their dens for longer periods of time.

"The longer they are out, the more likely they are to have an encounter, so we would anticipate a slight decline in survival rates," he said.

Researchers with the Trans-Canada Highway wildlife crossing project near Banff say they have noticed local bears are emerging earlier and denning later than ever before.

This year, a remote camera captured a grizzly bear crossing one of the highway overpasses on March 16, and last year, a grizzly bear was filmed on an overpass on March 25.

In 1999, the earliest grizzly appeared on May 27.

"It's kind of strange that it's happening," said Tony Clevenger, a senior research wildlife biologist who has been directing the long-term research project examining the effects of highways on wildlife populations.

"These bears are typically out and walking around a bit, but they don't go far. The fact that bears are down along the highway and fairly low in the valley is surprising."

Clevenger said it's not known if the shift in the hibernation patterns of grizzly bears is related to climate change, but "it is certainly an interesting phenomenon."

"It may not be representative of the entire population," he said. "This may be the wanderings and activity of a few restless males."

http://www.canada.com/calgaryherald/news/city/story.html?id=7cb0042b-d8cf-4788-8506-d79e7905ae76

ursusarctos

 

From here:

Muskox Bull Killed by
a
Barren-Ground Grizzly Bear,
Thelon Game Sanctuary,
N
.
W. T.
ANNE GUNN’ and FRANK L. MILLER2

INTRODUCTION
Muskoxen and barren-ground grizzly bears are relatively common along the banks of the Thelon River in the Thelon Game Sanctuary. In June 1981 we were flying a helicopter search of the Thelon River area during a study of water crossings used by barren-ground caribou (Rangifer tarandus groenlandicus). In the early afternoon of 23 June we were flying eastward when we spotted a grizzly bear standing on its hind legs among willow (Sulix spp.) bushes in a clearing surrounded by black spruce (Picea mariana) on the north shore. As there were two gulls (Larus spp.) in attendance, indicating the possibility of a kill, we circled closer and could then see a dead muskox on the ground near the bear. The grizzly bear alternately reared up and dropped onto all fours as we came close and when the helicopter was about 100-150 m away, the bear galloped away.
We landed near the carcass of an adult muskox bull lying on its left side. The carcass was intact except for some exposed flesh and head wounds. The nose was tom away and the nasal turbinal bones were crushed and the cartilage torn. The right ear was split and torn away at the base where there was a penetrating wound into the skull. Traumatized areas were hemorrhagic, indicating that the wounds were inflicted on a living animal. The hide and musculature had been removed in the lumbar and thoracic areas, exposing the vertebrae and the right scapula. The internal organs were still intact and warm to touch. Subsequent histological examination of the dental annuli of a first incisor indicated that the muskox bull was 9-10 years old.
The greening sedges (Carex spp.) immediately around the carcass were trampled and we backtracked along a disturbed path to a heavily trampled area of 5 m in diameter about 15 m away. The willow bushes peripheral to that trampled area were flecked with blood clots and clumps of blood-stained muskox wool.
The ground cover was beaten down and the ground surface disturbed in many places with footprints pushed 10-15 cm or more into wet soil. We suggest that the grizzly bear surprised the muskox bull while it was grazing on sedge (indicated by rumen contents). The bear most likely grabbed the bull above the muzzle. In response, the bull must have braced its front legs and tried to dislodge the bear, suggested by front-foot hoof prints driven deep (15 cm) into the churned-up ground. Either the bull collapsed or the bear swung him off balance. At that point, the bear probably transferred its bite to just below the back of the bull’s horn boss. After making the kill, the bear dragged the carcass to where we found it, and had begun feeding when we interrupted. We returned about 48 hours later and found a light grey wolf (Canis lupus) and a grizzly bear whose colouring suggested it was not the bear that had made the kill. The carcass was dismembered and had settled into the wet ground. Most of the muscle masses and the internal organs had been consumed and the limb bones were scattered around the hide. The rumen had been pulled from the carcass but had not been fed on.
The destruction of the facial area was also the mode of attack of a barren-ground grizzly bear killing a caribou cow whose carcass we found on the Beverly caribou herd’s calving ground, northeast of the Thelon Game Sanctuary, in June 1981. Griffel and Basile (1981) described puncture wounds in the frontal or jugal bones of 109 of 332 bear- killed sheep (Ovis aires) in Idaho. The facial area is richly innervated, and Mystervd (1975) in Griffel and Basile (1981) suggested that unconsciousness and hypoxic asphyxiation would follow severe and sudden injury to that area. Also, the seizing of the muskox bull’s muzzle would reduce chances of the muskox using its horns to gore the bear and increase the bear’s chances of throwing the muskox offits feet.
Solitary muskox bulls usually seem particularly alert, and their speed of response, size, strength, thick coat and horns must combine to make them a formidable quarry even for a grizzly bear. The location of this kill, at the edge of a small clearing where ambush by rushing from nearby cover was possible, suggests that the kill was opportunistic. The muskox bull was probably so intent on foraging on the new growth of sedges 10-20 cm high that he was not aware of his attacker until it was too late. The femoral marrow fat was pinkish-white and firm, suggesting good nutritional status, and we did not observe any obvious infirmities that would have made the bull particularly vulnerable.
Tener (1965) summarized predation on muskoxen and noted that Pederson’s report of a possible kill by a polar bear (Ursus rnaririrnus) may be the only reported instance of bear predation. He further commented that predation by barren-ground grizzly bears is rare, since up to 1965 only Hornby (1934, in Tener, 1965) had observed bears feeding on muskoxen on the banks of the Thelon River. In the late 1970s A.M. Hall (pers. comm.) observed grizzly bears feeding on muskox carcasses along the banks of the Thelon River (see photograph of grizzly bear sleeping near partially- eaten bull muskox in Hall, 1980). In 1978, on the banks of the Thelon, Hall observed three muskox carcasses on which grizzlies had fed, but he could not determine whether the bears had killed or were scavenging the muskoxen. Hall (pers. comm.) believes that grizzly bear predation on muskoxen is high, especially on solitary bulls along the Thelon River, probably because the dense willow stands favour surprise ambushes. In June and July 1981, we saw only solitary bull muskoxen feeding in the willow stands, which leads us to the same supposition. Within 40 km of the carcass described in this paper, during the same flight, we observed five other grizzlies on the north shore. Pegau (1973) briefly described an apparent kill of a 2- or 3-year- old muskox by a bear but the carcass was almost com- pletely consumed, so scavenging could not be ruled out. The carcass was found on the Seward Peninsula, Alaska, where Grauvogel (1979) speculated that the slow rate of increase of the transplanted muskox herd might be par- tially attributed to grizzly bear predation on muskox calves, though no evidence was cited. Our account of an apparently healthy, prime adult muskox bull that was killed by a grizzly bear is the first documentation of such an event.

taipan

 

related to Ursus' post above

GRIZZLY BEAR PREDATION ON MUSKOX
Sunday, July 27, 2008


Ovibos moschatus is a formidable beast that is sometimes preyed upon by grizzly bears.Photo Credit:US Fish and Wildlife Service.

The muskox (Ovibos moschatus) is a large ungulate (the average male weight is from 273 to 364 kg [600 to 800 pounds]) equipped with curved horns and a shaggy pelage which can be up to 10 cm (4 inches) thick. It is a close relative of the sheep or goats (subfamily Caprinae) and is able to withstand incredibly frigid, arctic conditions (down to at least – 70 ºF). Muskox tend to live in herds and are famous for their defensive posturing – they often form a defensive circle with their heads (i.e., armament) facing outward toward the potential threat. Youngsters often hide amongst the adults for protection.

The barren-ground grizzly bears and muskox overlap in their distribution in northern Canada and Alaska. This shaggy beast would appear to be fairly impervious to grizzly attack. But, this is not the case. Grizzlies were originally reported feeding on muskox by early explorers and with recent reintroduction of these ungulates in parts of the Arctic, there have been a number of papers written on the predator-prey relationship of U. arctos and O. moschatus. Below I have reviewed what is known about the barren-ground grizzly predation on muskox.

Multiple Hunting Strategy

In the Thelon Game Sanctuary, grizzlies and muskox coexist, but the relationship is not always copasetic. Near the Thelon River, bears may use thick willow stands along the waterway to ambush muskox feeding on sedge in nearby clearings. Willows also attract muskox, as it is a preferred food of this beast. Gunn and Miller (1982) report finding a bear on a freshly killed, bull O. moschatus. They were able to scare the adult bear off and examine its kill and concluded that the bear had dispatched the big ungulate by first grasping its nose (crushing the nasal turbine bones and tearing off the nose in the process) and then inflicting a crippling bite to its skull. By grasping the nose, the bear may have prevented the muskox from bringing its horns to bear and also may have been more effective at throwing the animal to the ground.

In another study carried out in the northeastern Arctic slopes of Alaska, 92 grizzly-muskox interactions were observed (Reynolds et al. 2002). Fifty percent of these were known kills, 40 % were possible kills or scavenging events, and 10 % were incidents where a grizzly was seen chasing muskox. It was estimated that 16-39 % of muskox mortality was the result of bear predation. During the study period (1982-2001) the number of muskox killed by grizzly bears was zero to two deaths per year before 1993, one to four musk ox per year from 1994-1997 and five to ten deaths per year from 1998-2001. This increase in kill numbers was a function of an increase in the size of musk ox herds. An increase in kills may also be indicative of the bears learning how to better attack and take down these big, formidable animals. While solitary adult bears were most often seen attacking muskox (69 occasions), pairs or trios of adult bears were seen chasing, killing or eating these animals (three episodes). Sows with cubs or yearlings were seen interacting with muskox on three occasions.

Surplus Killing

Grizzly bears sometimes engage in surplus killing of muskox. In the study carried out by Reynolds et al. (2002) there were ten episodes where one to three bears killed from two to four adult muskox. On several occasions even more muskox were dispatched during a single hunting bout. For example, in one case five individuals (two adult females, a yearling and unsexed adult musk ox) were incapacitated by a single bear. In another case, a grizzly killed four calves and in another incident the victims were one adult female, one two-year old male and one yearling. In most cases, solitary bears were involved in these killing sprees, but in one case three grizzlies instigated the melee.

Clarkson et al. (1993) reported a fascinating case of surplus killing of muskox calves by a heterosexual pair of adult grizzlies. Within a distance of about two km, the two bears took down five young musk ox. By doing a little forensic work, the researchers were able to put together a likely picture of what had happened. Rather than form a defensive circle to try and parry the bear attacks, this herd of musk ox tried to out run the grizzlies. The researchers postulated that the calves trailed behind the adults and, therefore, were more vulnerable. The two bears chased the herd, which consisted of 40 to 50 muskox (with a minimum of eight calves). They killed the first calf and ate 90 % of the carcass. They then chased the herd down again and about 1.5-2.0 km from the first kill dispatched a second young musk ox. They ate 60 % of this second calve and began the hunt again. They killed the third calf about 300 m from the second. The third calf was about 30 % consumed by the bears and a wolverine (Gulo gulo) that was feeding on the carcass when the researchers arrived on the scene. The fourth calve was killed 400 m from the third. A golden eagle had just begun to feed on calf four when the researchers arrived. The final calf was killed about 200 m from the fourth – this last young muskox was not eaten either.

http://gobiestogrizzlies.blogspot.com/2008/07/muskox-on-menu-grizzly-predation-on.html

taipan

 

ursusarctos

 

Taipan, I don't know the thread where you posted it, but once you posted a source in reference to grizzly mothers apparently often trading or adopting another's offspring, potentially undermining the dominant male's monopoly on the future generation's gene pool-rather curious, as I don't know how it would benefit the mothers, and certainly, the mothers should be able to tell their young apart from others, just as the young should be able to tell their mothers apart, considering their excellent noses.

Here it is :

taipan

 

Parenting Paradox



By Sharon Levy

Birds do it, so do mammals and fish, but why animals adopt unrelated offspring is an evolutionary puzzle


Such examples of familial devotion can be explained by an evolutionary theory known as kin selection. The idea is that genes that lead to an altruistic behavior--such as adoption--will spread as long as the behavior significantly enhances the survival and reproduction of the self-sacrificing animal's close kin. After all, an individual is just as related to a full sibling as it would be to its own offspring. In terms of passing on genes, then, caring for a close relative is the next best thing to having young of one's own--or perhaps a better option if an animal's offspring is unlikely to survive.

But even bears, solitary animals that normally have little contact with other adults, have been known to become adoptive parents. To test the possibility that polar bears take in orphans born to a close a relative--a mother or a sister--Nicholas Lunn of the Canadian Wildlife Service analyzed the DNA of mothers and cubs involved in three known cases of adoption. He found no evidence of genetic relatedness between any of the mothers and their adopted cubs.

It turned out that two of the polar bear mothers had swapped sets of twin cubs, and each was raising the other's young. In this case, confusion during a tense encounter with another family of bears is the most likely explanation. In the vastness of the Arctic, polar bears rarely encounter others of their own kind, so they have not needed to evolve a strong system for recognizing their own offspring.



MOSTLY MISTAKES: In the Arctic, an edgy encounter between two polar bear families can cause so much confusion that mothers accidentally switch their cubs. Because these encounters are relatively rare, the bears have not evolved a foolproof way to recognize their own offspring.

Both grizzly and Alaskan brown bears have been known to enlarge their families by adopting single or twin orphans, although the practice is uncommon. Among grizzlies, adoption happens most often at busy fishing spots where bears congregate to feast on huge salmon runs. The hubbub surrounding such food bonanzas may make it easier for orphans to seek out adoptive moms, and the availability of abundant food might make mothers more likely to accept a stranger. Yet cases of grizzly and brown bear adoptions remain unexplained. Bears do not share childcare with members of a pack like wolves do. Why would they take on extra cubs, and decrease their own offsprings' chances?

Even more difficult to explain is why an animal--such as that Sanibel Island raccoon--would adopt the offspring of a different species. Boness and Brown both suggest that the raccoon may have taken in the kitten by mistake while her own babies were very young. In captivity, dogs with young puppies have been induced to suckle cats, and cats have nursed rats. Mothers in these experiments accepted the alien offspring before their own young were old enough to move around, the point at which powerful recognition systems usually kick in.

Still, it's hard to interpret such adoptions as anything other than reproductive bloopers. According to Jablonka, biologists understand very little about cross-species adoptions in the wild. "There are few reports of this behavior," she says, "and I suspect its occurrence is underestimated."

Sometimes, when the urge to nurture overwhelms, animal parents can end up in bizarre situations. In the mid-1970s, a biologist working in Alaska observed a pair of arctic loons, which had lost their own chicks, raising five spectacled eider ducklings that might otherwise have made a decent lunch. More recently, a lioness in Kenya's Samburu National Park took in a newborn Beisa oryx--normally a prey species--then attempted to adopt a second baby oryx after game wardens took away the first. Despite such occasional parenting blunders, the persistence of adoption suggests that even in the unsentimental calculus of natural selection, it may be better to err on the side of compassion.

http://www.nwf.org/nationalwildlife/article.cfm?articleId=516&issueId=45

ursusarctos

 

Thanks Taipan,
Evolution has made humans take care of babies through causing us to think they are cute.
Therefore, we are likely to even take care of the young entirely different species of animals.
I theorize maybe something is different there?
Of course, cub-killing males, who naturally don't take care of young, wouldn't have such feelings in any of these non-social species, although, lions are an exception, where the males are both cub-killers (when they take over a pride), and protectors and parents of cubs...
No idea what the actual reason is, but it may be simply related to the instincts that drive the mothers to take care of their own young.

Quote:

 

Because these encounters are relatively rare, the bears have not evolved a foolproof way to recognize their own offspring.

With a smell that lets them recognize so much information about individual adults (beyond telling them apart), I fail to see how they couldn't recognize the difference between their own young. The fact a mother wouldn't endeavor to retrieve the young she's lost seams peculiar, however.

EDIT:

Chart (from here) showing brownie sizes and degrees of sexual dimorphism.
It is interesting to see that males in some areas average at about twice as heavy as females.
Based on the line, it appears that the male brown bears from any given region will typically weigh roughly two thirds more then the females.

gatogordo

 

Grizzly bear vs cattle interactions.

I found two interesting sources on predation of grizzly bears on cattle:

Source #1

Grizzly Bear (Ursus arctos)
Final Biological Assessment

for the

Forest Plan Amendments for Grizzly Bear Conservation
for the Greater Yellowstone Area National Forests
Beaverhead-Deerlodge National Forest
Bridger-Teton National Forest
Caribou-Targhee National Forest
Custer National Forest
Gallatin National Forest
Shoshone National Forest

August 2005

Available at:

www.fws.gov/mountain-prairie/species/mammals/grizzly/BAFinal09222005.pdf


Grizzly Bear/Livestock Interactions (See page 26)

Knight and Judd (1983) reported the following information about bears that kill livestock:

• All instrumented (radio-collared) grizzly bears known to have had the opportunity (bears that came in close contact with sheep), killed sheep.

• Most grizzly bears that encountered cattle did not make kills.

• All known cattle killers were adult bears, while sheep killers included both adults and subadults.

• They concluded that sheep grazing in occupied grizzly range is a serious problem, since bears kill sheep more readily and because the sheep are closely tended by herders that are protective of their flocks.

Anderson et al. (1997) reported the following information from a study on grizzly bear/cattle interactions on two cattle allotments in northwest Wyoming:

• From a minimum of 24 grizzly bears that were known to use two cattle allotments during a three- year period, seven bears (possibly eight) preyed on cattle.

• Thirty percent of 194 cattle mortalities documented during the three years were the result of bear predation, 65% were not bear-related, and 5% were classified as unknown.

• Predatory grizzly bears selected calves (51 of 58, or 88%) over adult and yearling cattle.

• All sex/age groups of grizzly bears, except subadult male, were associated with cattle depredations. However, three adult males were responsible for 84% of the documented losses where individual depredators could be identified.

• Cattle depredations were limited to a relatively short period (three to eight weeks) during two of the three grazing seasons, and five of the eight bears suspected of killing cattle did not appear to kill more than one calf each.

• Translocating grizzly bears appears to be a viable option for reducing losses, since homing bears may not return before that depredation period ends. Additionally, translocation could prevent the occasional depredator, which appears to be common among grizzlies, from being unnecessarily removed from the population.

• Removing cattle carcasses from allotments also appeared to reduce bear densities, but it could not be determined whether this would reduce depredations.

• Since adult males are responsible for the majority of cattle depredations, selective removal may also be a possible management option, particularly when habitual adult males are involved and translocation, aversion tactics, or carcass removal efforts are ineffective.

In summary, most, if not all, grizzly bears that come in contact with domestic sheep prey on sheep and conflicts are inevitable. Within the PCA, 40% of the sheep allotments active in 2003 have had documented grizzly bear conflicts. Several sheep allotments that have had conflicts with grizzly bears have been closed.

The majority of grizzly bears that come in contact with cattle do not make kills. Within the PCA, 24% of the cattle allotments active in 2003 have had documented grizzly bear conflicts. Conflicts between livestock and grizzly bears have resulted in the relocation, removal, or direct mortality of grizzly bears. Many of the conflicts with grizzly bears and sheep have been resolved inside the PCA due to the closure of many of the affected allotments. Conflicts with livestock have increased in recent years primarily outside the PCA.

There were 478 documented grizzly bear/livestock conflicts on the six national forests from 1992 to 2004 (Figure 11). However, only 10% of the documented grizzly bear mortalities since 1975 have been livestock related (Figure 8).


Articles cited

Knight, R.R. and S. Judd. 1983. Grizzly bears that kill livestock. International Conference on Bear Research and Management 5:186-190.

Anderson, C. R., M. A. Ternent, D. S. Moody, M. T. Bruscino, and D. F. Miller. 1997. Grizzly bear-cattle interaction on two cattle allotments in northwest Wyoming. Wyoming Game and Fish Department, Lander, Wyoming. 87 pp.

Source #2


Grizzly bear–human conflicts in the Greater
Yellowstone ecosystem, 1992–2000

Kerry A. Gunther1,6, Mark A. Haroldson2,7, Kevin Frey3,8, Steven L. Cain4,9,
Jeff Copeland5,10, and Charles C. Schwartz2,11

Available at

http://www.nrmsc.usgs.gov/science/igbst/pubs

Livestock predation is discussed in the following paragraph

Livestock depredations. Incidents of depredation
on livestock comprised 44% (n = 436) of the total conflicts
reported. Livestock depredations included incidents with
cattle (71%, n = 311), sheep (27%, n = 116), horses (n = 3),
chickens (n = 3), ducks (n = 2), and turkeys (n = 1).

Livestock depredations occurred on public (80%, n = 349)
and private (20%, n = 87) land, both inside (31%, n = 134)
and outside (69%, n = 302) the YGBRZ. All incidents of
grizzly bears depredating horses, chickens, ducks, and
turkeys occurred on private land.

Multiple kills within
a single incident were common when grizzly bears
depredated sheep (59%, 68 of 116 incidents), chickens (3
of 3 incidents), ducks (2 of 2 incidents), and turkeys (1 of 1
incident), but rare when they preyed on cattle (2%, 7 of
311 incidents) and horses (0 of 3 incidents). With sheep, 1
to 133 sheep were killed and averaged 4.3 sheep/incident.
With cattle, 1 to 3 cows were killed and averaged 1.03
deaths/incident.

Most livestock depredations occurred
during early (58%, n = 251) and late (25%, n = 109)
hyperphagia (Table 1). The number of incidents of
livestock depredation increased (Fig. 5) significantly from
1992 through 2000 (b = 5.98, F = 7.92, P = 0.02).
Livestock depredations increased significantly outside of
the YGBRZ (b = 7.12, F = 29.08, P = 0.01) and on private
land (b = 2.00, F = 11.05, P = 0.01), but not inside the
YGBRZ (b = 1.13, F = 0.94, P = 0.36). There was also
a strong increasing trend for livestock depredations on
public land (b = 3.98, F = 3.65, P = 0.09).


COMMENTS:

• 
  
• Bears predate much more sheep than cattle, but they do take cattle and even horses
  
• Bears select strongly for calves (88% of all cattle kills in one report)
  
• Surplus killing was recorded with smaller prey (sheep, turkeys, chicken), rarely with cattle and not at all with horses
  
• The articles do not describe the killing method, but there is a forensic study by A Murie describing cattle as killed by bites to their necks, not by blows.
  

taipan

 

taipan

 

Saving Spanish Brown Bears With Help From European Bears Might Make Sense

ScienceDaily (Mar. 19, 2008) — Brown bears from the Iberian Peninsula are not as genetically different from other brown bears in Europe as was previously thought. An international study being published in Proceedings of the National Academy of Sciences, shows that, to the contrary, the Spanish bear was only recently isolated from other European strains. These findings shed new light on the discussion of how to save the population of Spanish bears.

The researchers extracted DNA and determined the gene sequence of bears from prehistoric material, primarily from the Iberian Peninsula. Some of the material was as much as 80,000 years old. When the data material was analyzed, what emerged was a totally unexpected pattern.

"We expected to be able to follow the Spanish brown bear far back in time, but we found to our amazement that it had genetic material from bears in other parts of Europe. In fact, it seems that the Spanish bear was isolated for the first time in our own time," says doctoral student Cristina Valdiosera, who performed most of the laboratory and analytical work.

"These bears have possibly been isolated in Spain for a few thousand years, which is a very short period in an evolutionary perspective. In other words, there has been a flow of genes to and from the Iberian Peninsula throughout most of the time brown bears have been there. This is extremely interesting data when we discuss transporting bears from other areas to Spain for the purpose of preservation," says Anders Götherstam, who directed the study.

The number of bears on the Iberian Peninsula is limited, with the population divided into two small groups in the north. In-breeding and genetic depletion constitutes a serious threat to the bears' survival in this area. For preservation purposes, the possibility of introducing bears from other areas to the Iberian Peninsula has been discussed, but it has been argued that this would entail the extinction of the genetically unique Iberian bear. It has also been feared that bears from other areas are not as well adapted to the living conditions on the Iberian Peninsula as the Spanish bears are.

"But since there has never been a genetically isolated brown bear on the Iberian Peninsula until very recently, these arguments can be questioned," says Anders Götherstam.

The study was performed collaboratively by scientists from Spain, France, Germany, the UK, and Sweden.


A new study shows that the Spanish bear was only recently isolated from other European strains.

Adapted from materials provided by Uppsala University.

http://www.sciencedaily.com/releases/2008/03/080318094519.htm

Two Brown Bear Populations In Spain In Danger of Extinction Have Been Isolated For Past 50 Years

ScienceDaily (Apr. 29, 2009) — The situation of bears in the Iberian Peninsula is critical. Researchers from the University of Oviedo (UO) and the Superior Council of Scientific Research (SCSR) have performed a genetic identification based on the analysis of stools and hair of brown bears (Ursus arctos) from the Cantabrian mountain range, gathered between 2004 and 2006.

The non-invasive analysis of 146 samples has allowed for the identification of 39 bears in the western sub-population, and 9 in the eastern one, so as to show the genetic structure of the population. In order to obtain the individual genotypes of the bears, scientists have employed 18 micro-satellite markers in a joint fashion, and a sex marker with high-class genetic technology.

"The level of genetic diversity was 45% in the western sub-population, and 25% in the eastern population¨, explain Trinidad Pérez and Ana Domínguez Sanjurjo to SINC, authors of the study and researchers at the Department of Functional Biology (Genetics) at the UO.

According to Pérez, these levels of gene variation (which allow for adaptation, survival and evolution of the species) are ¨among the lowest of those described in scientific literature for this species¨.

The study, which appears in the latest edition of the magazine Conservation Genetics, points out that the difference between the two Cantabrian sub-populations is ¨extreme¨, around 41%. This value is comparable, for example, to that of the chamois (Rupicapra), which are considered a different species.

For Domínguez Sanjurjo, this phenomenon ¨can only be explained by an absolute isolation between both sub-populations, joined with an extremely reduced size in the eastern¨. From this differentiation data between sub-populations, ¨it can be inferred that there has been no genetic flow between them for at least 50 years¨, affirm the scientists.

In this fashion, we know that in the eastern population, the endogamy rate (reproduction of individuals from the same lineage) per generation is approximately 10%, ¨a value with amply exceeds the maximum tolerable rate given for domestic animals, which is 1%¨, asserts Pérez to SINC.

The sub-population has a number of around 20 individuals, a number which ¨is very far from the size considered as a viable minimum, which means its short-term conservation is seriously compromised¨, adds the biologist.

On the other hand, the western sub-population presents moderated levels of diversity, ¨probably due to an important reduction in the number of bears which would have begun 300 years ago¨, highlights Pérez. Although at the end of the 90s, the estimated size of this sub-population was between 50 and 60 members, ¨this number should be situated around 200 individuals for the bear population to be viable short-term¨, declare the scientists.

Connecting populations, a solution

In spite of the fact that the eastern population has less individuals, the western one possesses ¨a great risk of extinction in the near future¨, points out Domínguez. To this end, the researchers explain that ¨the connectivity between the two sub-populations is priority if we want to maintain the eastern nucleus, which would be at risk of immediate extinction¨.

The genetic analysis has allowed for the identification of a macho individual in Palencia belonging to the western sub-population. ¨In theory, if one migrant from one sub-population managed to reproduce with another every 10 years, it would reduce the differentiation between the two bear populations by 20%¨, confirm Pérez and Domínguez. The genetic difference would diminish by 11% if they were two bears. ¨This migration would increase diversity in the eastern sub-population, considerably increasing their possibilities of survival¨, points out Pérez.

In order for the brown bears to be out of danger long-term, ¨it would be necessary to control the population as a whole, estimate size and tendency, procure connectivity between the two sub-populations and avoid losses of habitat¨, conclude the researchers.


The situation of bears in the Iberian Peninsula is critical.
--------------------------------------------------------------------------------

Journal reference:

1.Pérez et al. Non-invasive genetic study of the endangered Cantabrian brown bear (Ursus arctos). Conservation Genetics, 2009; 10 (2): 291 DOI: 10.1007/s10592-008-9578-1

http://www.sciencedaily.com/releases/2009/04/090429125243.htm

ursusarctos

 

I hope that they do something. It is always sad to see large animals die out, even if it is only a sub group. Same applies to the critically endangered Amur leopard and Iberian lynx.

Brown bears evidently display two distinct types of fighting; from Warsaw:
Aggressive behaviors of the japanese brown bear
D. Caroline Blanchard 1 *, Robert J. Blanchard 1, Toshiaki Takahashi 1, Nobuo Suzuki 2
1Department of Psychology, The University of Hawaii, Honolulu
2Department of Psychology, University of Hokkaido, Sapporo, Japan

Abstract
Film analysis and direct observation suggest that 2 very different types of intra-specific fights occur among Japanese brown bears maintained in large stable colonies. Disputes arising over food are short, and involve such activities as threatening, muzzling, chasing, and flight. Weapon use during feeding fights primarily involves slashing blows to the back or head areas of the opponent. In contrast, spontaneous fights are longer, and consist almost exclusively of wrestling, with bites and forepaw blows directed at the opponent's ruff area. These spontaneous fights occur primarily among the larger and higher-ranked male bears, especially among animals with closely adjacent rankings. It is suggested that such fights facilitate the establishment of dominance relationships by providing an opportunity for mutual assessment of strength and stamina without serious risk of injury.
http://www3.interscience.wiley.com/journal/112418421/abstract?CRETRY=1&SRETRY=0
http://tinypic.com/player.php?v=xbmexz&s=5

Bear (I think this may be general to North American bears; I don't remember, although the source was Bear Attacks by Stephen Herrero) agnostic behavior patterns:


Brown bear body fat percentages:



[EDIT: just wanted to note that Gau 1998 is where table 6 above was taken from. It is mentioned in the above quote, which is from a source I once had saved years ago but have since lost. Worth noting that the 6.3% and 33.6% figures mentioned are from table 6, and represent extremes as the quote says.]



For comparison, human fat levels (chart taken from wikipedia):

firefly

 

«I hope that they do something. It is always sad to see large animals die out, even if it is only a sub group. Same applies to the critically endangered Amur leopard and Iberian lynx.»- Ursus.

Brown bears on Iberian Peninsula are fortunately getting more numerous now, especially on the western population.
Some were spot on the portuguese/spanish borders on the Sanabria region, which clearly indicates that they are new brown bears exploring new possible territories, much further than the previous thought only location ( North Cantabrian mountains).
Concerning the iberian lynx, about the one I already did some works, a pair was found to live inside a big cork oak farm, in South Portugal, which remind us how elusive ( no one would think that such a specie would live there...) and rare are these creatures.
A new Captive Breeding center is now operating also in Portugal, because of the great sucess that the Spanish Center had which turned possible the chance of donating lynxes to the portuguese side.
I hope that the portuguese get some wild lynxes from their country, to increase the genetic pool of the captive population.
Spanish are waiting for results regarding this subject.
On USA how are doing brown bears?

ursusarctos

 

Diet of grizzly bears:

Notes to Tables
The differences between food habits, fecal volume, and assimilated diets for grizzly bears. Fecal volume was estimated by sorting the contents of feces collected in the field, food habits was estimated from fecal volume by correcting for differential disappearance, and assimilated diet was estimated by multiplying the concentration of energy and protein in each food by its digestibility (adapted from Pritchard and Robbins 1990, Hewitt and Robbins 1996, Rode et al. 2001)

From Nutritional ecology of ursids: a review of newer methods and management implications.

In particular, 54% of the dry matter consumed by grizzly bears is ungulates.

reddhole

 

Grizzly mauls sheepherder; kills dogs, sheep
Posted: Tuesday, Sep 15th, 2009
BY: Joy Ufford with Derek Farr



After what could be the first grizzly bear attack on a human in the Upper Green, a 46-year-old sheepherder was life-flighted to Idaho Falls early Monday morning after being seriously mauled.

The grizzly began its rampage in the early hours in a sheep herd grazing near Forest Road 617, at the eastern edge of the Gros Ventre Wilderness near Tosi Creek.

The herd is tended by Marcello Tejeda, of Rock Springs, and Jorge Mesa, both of whom were awakened by what they thought was a black bear in the sheep, according to their employer, rancher Mary Thoman of Fontenelle.

Monday, Thoman was concerned for Tejeda and her sheep, which have been harassed by predators all summer, she said.

“We have had a nightmare,” she said of the W&M Thoman Ranches’ forest allotments on the Upper Green. “Nothing but grizzlies and wolves all summer long.”

At 3:30, the Sublette County Sheriff’s Office received a call from Mesa that a bear had attacked a man and that an ambulance or doctor was needed to help him, according to preliminary reports.

Thoman said they have always had problems with black bears getting into the sheep but the grizzly situation has been worsening since 1998 when she said grizzlies were moved into that area from elsewhere.

“The dogs were raising heck and they thought it was a black bear,” Thoman said her sheepherder told her.

This was a grizzly sow with one cub, though, she was told. Thoman said she recently saw a collared grizzly sow with three cubs that had “just showed up” but didn’t know if they were the same animal.

The guard dogs stay with the sheep and protect them as best they can, she explained.

“Once they found out a bear was in the sheep the sheepherder (Tejeda) sent his (guard) dog in and the bear killed that one,” Bardin related .

Tejeda then sent in another guard dog and apparently was attacked by the bear when he tried to save the second dog, which was killed, he said.

The sheepherder received a seven-inch gash on top of his head, two punctures to the left side of his chest, three claw wounds to the right side of his abdomen and a puncture wound to his right wrist, early reports stated.

“This is the first human attack there that I can remember,” Bardin said.

Mesa used pepper spray – twice – to drive the bear away from Tejeda and then called Thoman for help.

Thoman said giving her sheepherders guns to shoot marauding predators isn’t a solution – “or we just have more trouble.”

Mesa then notified the sheriff’s office, and a team was sent in including an Emergency Medical Services unit, Kendall Valley Fire Department’s first-responders, three deputies and a Forest Service officer while Air Idaho, a search-and-rescue team and a doctor were put on standby.

Because of the poor travel conditions, a deputy drove Tejeda and Mesa (who had pepper spray in his eyes) out to a waiting ambulance and they were transported to the Pinedale Clinic.

Mesa’s eyes were cleaned and Tejeda was airlifted to Eastern Idaho Regional Medical Center (EIRMC) in Idaho Falls.

Tejeda was listed in “serious” condition Monday afternoon, according to EIRMC spokesperson Nancy Browne.

Wyoming Game & Fish team investigated the scene of the attack Monday.

“We’ve heard this person has been injured and that’s our primary concern,” said G&F spokesman Mark Gocke. “We hope he’s all right.”

Gocke had no further information Monday but said G&F is participating in the investigation and more details will be forthcoming.

Predators have heavily targeted sheep and cattle on Upper Green permitted grazing allotments this year, according to Thoman.

Most of the publicly confirmed predations are sheep killed by wolves but there are plenty of others in the mountains.

Thoman said she can’t put a number to their losses yet, not until the herds are gathered and brought back home.

“What they verify doesn’t match up, though,” she said of investigating agencies.

“The trouble is by the time you notify them, if they don’t get there within three or four days they can’t confirm,” she said, adding other animals will feed on the carcasses.

“We just have to put up with them,” she said. “They need to put them away. They’re just getting too thick.”

Thoman said most people don’t realize how heavy livestock losses are in the Upper Green and public land managers seem to not care – “I think they’re just trying to get rid of us (livestock ranchers).”

Thoman doesn’t plan on giving in to bears, wolves or public agencies lightly, she said. Thoman sheep have grazed on the same allotments since 1978 and her family began ranching before 1900.

“It isn’t like we just sprang up,” she said.


Predators

On Aug. 6, Wildlife Services confirmed a grizzly had killed two head of cattle in the Upper Green.

In a slew of late July and August attacks in western Wyoming, wolves killed dozens of sheep, a handful of cattle and a half-dozen guard dogs, according to U.S. Fish and Wildlife Service (FWS) reports.

Recent reports reveal lethal control efforts have removed 10 wolves to date from the Green River Pack and five from the Dog Creek Pack.

Thoman worries that wolves and bears have run the sheep around so much that right now without anyone up there to keep an eye on them, her herds could be scattered throughout the forest.

“I suppose we’ll be hunting sheep up there until Christmas,” she said.

No one from the Forest Service, which manages the grazing allotments, responded before press time.

http://www.subletteexaminer.com/V2_news_articles.php?heading=0&page=72&story_id=1258

taipan

 

French Male Bears In Immediate Need Of More Females

ScienceDaily (Oct. 29, 2009) — The population of brown bears (Ursus arctos) in France is now so small that the species might become extinct in the near future. However, there is new hope in the form of new research published October 28 in PLoS One, which suggests that relocating new bears doesn't just boost the population size but can also reverse some of the causes of the population decline.

"Our results suggest that having a viable bear population in France requires further translocations. In particular, male bears need more females," says Guillaume Chapron from the Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Sweden and colleagues from the Washington State University, USA, and the Office National de la Chasse et de la Faune Sauvage, France.

French brown bears are currently found only in the Pyrénées mountains in two sub-populations: the growing central population, created from a previous translocation and the endemic western one, which is believed to be in decline because of excessive human-caused mortality and inbreeding.

The researchers analyzed field data collected from 1993 to 2005 and found that the western sub-population had much lower reproductive success than the central sub-population. They suggest this could be the consequence of the western sub-population being inbred or having a male-biased sex ratio. In species with extended parental care, a male-biased sex ratio can induce sexually selected infanticide, a behavior in which males attempt to kill unrelated cubs to induce estrous in females, maximizing their opportunity to breed.

Chapron and his colleagues used a population model to compute how many bears should be released to ensure viability, and showed the population could recover provided an adequate number of new females are translocated. The most recently collected field data will now be used to update their population model.

These findings are also important for conservation biology more generally. The usual recommendation when planning a translocation is that it should not take place until the causes(s) of the decline has been reversed. The opposite is true, according to Chapron and colleagues, who suggest that a translocation could take place, even if the decline has not yet been reversed, if the translocation itself removes the biological mechanisms behind the decline.

Funding and support was provided by the Centre National de la Recherche Scientifique (CNRS); Museum National d'Histoire Naturelle (MNHN) Departement Ecologie et Gestion de la Biodiversite; National Science Foundation (NSF) grant # 0423906; Office National de la Chasse et de la Faune Sauvage (ONCFS); Universite d'Angers; Universite Pierre et Marie Curie; Washington State University, University of Bern and Swedish University of Agricultural Sciences.


Male bear. The population of brown bears (Ursus arctos) in France is now so small that the species might become extinct in the near future.
--------------------------------------------------------------------------------

Journal reference:

Chapron et al. Diagnosing Mechanisms of Decline and Planning for Recovery of an Endangered Brown Bear (Ursus arctos) Population. PLoS ONE, 2009; 4 (10): e7568 DOI: 10.1371/journal.pone.0007568

http://www.sciencedaily.com/releases/2009/10/091028090534.htm

ursusarctos

 

The article "Social Behavior of Brown Bears on an Alaskan Salmon Stream" is one I found very interesting. It is largely about the interactions between bears of different age and sex classes.

The things I've found most interesting are those with the bold title, so feel free to skip to those if you're not particularly interested in brown bears, as I know this post is fairly long.

The basic purpose of the study is as follows:

For two summers (1972 and 1973) they observed the upper terminus of McNeil Falls were the bears congregate in order to fish; most bears were said to ignore their presence, although large males avoided the area if more than 3 or 4 people were there, and some other bears stayed away and wouldn't cross to their side of the river.

Info on the methodology:


How each age/sex class was defined:


Many bears stayed for an extended period of time; 27% for 30+ days, with another 47% for at least half the season.

Early and midmorning is when activity was lowest, and it peaked between 6 and 7 pm.
Activity dropped heavily after 10 and 11 pm-which is noteworthy. No more than three bears were active at night.

Types of interactions fall into these categories:

A brief description of each (from the article):
Head held low threat: bears generally at less than 4 meters, with the head held below the horizontal line of the body. Roared slowly while opening and closing their jaws.
Head held high: Less than 0.2 meters apart. Heads held diagonally upwards, with jaws open, both acting like they're about to lock jaws. Body weight shifted to the back legs to free up arms for striking or defending. Roared loudly.
Charges: Three charge types; each involved running straight at the other bear, with eyes fixed on target. One involved a quick break off (breaking off the attack after only 3-4 strides). Another was a complete charge, and the final one a combination of threat and avoidance.
Contact: striking, and sometimes biting. Biting normally aimed at head and neck, striking apparently mostly at the chest and shoulder (this'll surely interest Taipan!).
Play is play, and amicable is like a greeting, or extremely short play bout.

The most common agnostic interaction was a bear avoiding another, or withdrawing upon the approach of another.

Bears sometimes did a good job of ignoring each other, and often only react with slight changes of body orientation/head movements.

These types of behaviors were all heavily associated with the age/sex groups.
Data on frequencies:


Cause of low frequency of adult male aggression in the above data:


The extreme aggression of adult males causes all other bears to avoid them, and, once they begin to arrive in the evening at 10-11 pm, the other bears clear out, causing the huge drop in activity.


Contrast this to the aggression of the adolescent males, who are also sexually mature, and therefore may be considered adults:

A completely different animal, and a fact that should be considered when interactions between brown bears and other animals occur.

Females with cubs were the only class that was aggressive enough to challenge adult males consistently:

Although they, too, were generally submissive and retreated.

Info on adolescent females:


How I found the article was through searching for information on pairs of subadult bears, and eventually I found this article. To bad no information is given.
Their greater aggression than adolescent males is interesting.

The lack of information pertaining to subadult coalitions suggests that these certainly do not help in giving the bears any appreciable social status to feed in the more productive feeding areas, and/or that they're very loose.

And unsurprisingly quantity of food ties into how aggressive the bears are.
It is then mentioned that greater salmon levels were also associated with an increase in levels of non-agonistic interactions.

And there are some amusing anecdotes, such as an adult male running from a much smaller adolescent:

Presumably, the adult male was a fairly low ranking one itself, and thus not very confidant if it wasn't familiar with the other bear.
At the beginning of the year encounter rates were therefore at their lowest, at 0.44 per hour in 1972 and 0.8 per hour in 1973, compared to 1.49-2.37 per hour for the rest of the season.

Fleeing and chasing was initially often common, as one of the (normally juvenile) bears that spontaneously runs is chased by another. Fleeing bears eventually turned to face their pursuers if chase was extended; when fighting was involved, normally the chased bear initiated it.
Description of initial changes:

And the accompanying table 3:


Head-low threats increased with time, while head high threats and fighting remained relatively constant.
Bears dominant over others were much more likely to initiate interactions than vice versa.

Two tables relating to these changes over time:



Salmon abundance again is found to be highly related to aggression:


The winner of an encounter is defined by the following criteria:



And in interactions between members of each sex/age class, the results are:


Explanation for variation between years:


The hierarchy isn't always linear:

For future note, Number 22 is the alpha male.

And the importance of dominance:


It is also mentioned that bears have greater success in fishing in the mid afternoon and evening, and thus while subordinate bears may have good fishing spots in the early morning, they are supplanted by the mid-afternoon.

Part of the conclusion and comparison with other Carnivora:


Behavior of the alpha male:



It certainly paints an impressive picture of the top-brown bears, and their extreme aggression as well as exertion of dominance; along with his extreme intolerance of other bears over the two years he was observed he never lost an encounter.

Females more receptive to small, young, males:


Very unusual considering how this contrasts from known behavior of other species...

taipan

 

Grizzly Bears Move Into Polar Bear Habitat in Manitoba, Canada

ScienceDaily (Feb. 23, 2010) — Biologists affiliated with the American Museum of Natural History and City College of the City University of New York have found that grizzly bears are roaming into what was traditionally thought of as polar bear habitat -- and into the Canadian province of Manitoba, where they are officially listed as extirpated. The preliminary data was recently published in Canadian Field Naturalist and shows that sightings of Ursus arctos horribilis in Canada's Wapusk National Park are recent and appear to be increasing in frequency.

"Grizzly bears are a new guy on the scene, competition and a potential predator for the polar bears that live in this area," says Robert F. Rockwell, a research associate at the Museum and a professor of Biology at CUNY. "The first time we saw a grizzly we were flying over the middle of Wapusk, counting fox dens, when all of the sudden Linda Gormezano, a graduate student working with Rockwell and a co-author of the paper, shouted 'Over there, over there -- a grizzly bear.' And it wasn't a dirty polar bear or a moose -- we saw the hump."

That sighting in August 2008 spurred Rockwell and Gormezano to look through records to get a better picture of the bear population in the park. There was no evidence of grizzly bears before 1996, not even in the trapping data from centuries of Hudson Bay Company operation. But between 1996 and 2008 the team found nine confirmed sightings of grizzly bears, and in the summer of 2009 there were three additional observations.

"The opportunistic sightings seem to be increasing," says Gormezano. "This is worrying for the polar bears because grizzly bears would likely hibernate in polar bear maternity denning habitat. They would come out of hibernation at the same time and can kill polar cubs."

Before this study, researchers thought that the barren landscape north of the Hudson Bay was an impassable gap in resources for potentially migrating grizzly bears. But some U. arctos horribilis have managed to move from their historic ranges in the Rockies, the Yukon, and Nunavut, probably because of their flexible, mixed diet of berries and meat. The potential gap was navigable, and now some grizzly bears have reached the abundant caribou, moose, fish, and berries found to the south in Canada's Wapusk National Park.

"Although we don't yet know if they are wandering or staying -- the proof will come from an observed den or cubs -- these animals will eventually be residents of this national park," says Rockwell. "The Cree elders we talked to feel that now that grizzly bears have found this food source they will be staying."

"A big question is how to deal with these new residents," continues Gormezano. "In Canada, both the polar and grizzly bear are federally listed as species of special concern. In Manitoba, the polar bear is provincially listed as threatened while the prairie population of the grizzly bear is listed as extirpated."

In addition to Rockwell and Gormezano, this paper was authored by Daryll Hedman of Manitoba Conservation in Canada. This research was supported in part by the Hudson Bay Project.


This is a grizzly Bear (Ursus arctos), photographed in Wapusk National Park, Manitoba, Canada, on August 9, 2008.

http://www.sciencedaily.com/releases/2010/02/100223121439.htm

ursusarctos

 

Golden Bears/Grahhh found the following info on grizzly predation on elk:

Grizzlies apparently do prey on adult elk, although they are less preferred than moose (who are preyed on more relative to their proportion of the population of prey animals).
A couple of the extracts Golden Bears/Grahhh chose to post from the article:

Quote:

 

Among the ungulates, elk were by far the most important prey. This was basically a density-depen­dent relationship, since elk outnumbered all other ungulates combined. Elk were most vulnerable at three periods during the annual life cycle: the rut­ting season, the end of winter, and at calving.

Quote:

 

During and after the rutting season, bull elk are more vulnerable to grizzly bear attacks than at other times when grizzlies may selectively hunt them. Bulls become vulnerable in fall because of their habit of bugling, their strong rutting scent, and their preoc­cupation with mating and holding a harem. Many also receive incapacitating wounds in combat with other contending males. Any of these situations may trigger predatory behavior in the bear, which then uses the combination of skills most appropriate to the specific opportunity.

taipan

 

taipan

 

It wouldnt be out of the norm for that to be from an act of predation :

frank

 

BOZEMAN, Montana — Grizzly bear numbers in and around Yellowstone National Park have hit their highest level in decades, driving increased conflicts with humans as some bears push out of deep wilderness and into populated areas.
Scientists from a multi-agency research team announced recently that at least 603 grizzlies now roam the Yellowstone area of Wyoming, Montana and Idaho. That's more than three times the number in 1975, when hunting was outlawed and the species placed on the endangered list.

But more bears also means more run-ins with humans — although bear biologists are quick to point out that visitors to the region are more likely to die in a vehicle crash than a grizzly mauling.

Two people have been killed by grizzlies in the Yellowstone region this year: one in Wyoming and another in Montana.


READ MORE: Montana bear attack puts hikers and campers on alert

Despite their growing numbers, Yellowstone-area bears remain protected as an endangered species. The U.S. Fish and Widlife Service took away those protections in 2007, but they were restored last year by a federal judge.

That decision is under appeal. Federal grizzly recovery coordinator Chris Servheen said that a decision on the appeal is not expected until 2012.

In the latest encounter with a grizzly, last week, a hunter in Wyoming reported to authorities that he was attacked by a bear that he shot and killed in self-defense.

The man, whose name was not available, suffered lacerations from a bite to the leg. The injuries were not considered life threatening.

The incident remained under investigation and the death of the bear was not immediately confirmed. It would mark the 46th grizzly killed or removed from the wild this year. Factoring in unreported killings, wildlife officials estimate at least 62 bears killed or removed so far this year.

The last time so many bears died, in 2008, the population dipped the following year.

But the head of the grizzly research team said only 11 of the known bear deaths were adult females, dampening worries that the species' long-term recovery could stall.

"Our population is strong, our counts of females are high," said Chuck Schwartz, a U.S. Geological Survey scientist who heads the Interagency Grizzly Bear Study Team. "Right now, all indications are we haven't turned into negative trajectory."

Schwartz added that the 603 population figure was a conservative estimate and that the true number could be significantly higher.

Wildlife advocates have been more skeptical of the grizzly's future. They point to the decimation of a key bear food source — the nuts of whitebark pine trees — as a potential threat to the species' long-term survival. Vast stands of the trees are dead or dying because of beetle infestation.

Government scientists including Schwartz said bears adapt quickly to annual changes in the food supply and were unlikely to be impacted by the loss of a single food source.

Between 2004 and 2008, the area inhabited by Yellowstone grizzlies expanded 34%, to more than 22,000 square miles (57,000 sq. kilometers).

Wildlife managers said that push outward from Yellowstone National Park has created a number of "hot spots" for conflicts.

In Wyoming, that expansion helped fuel a record 251 conflicts between bears and humans so far this year, ranging from tipped over garbage cans and killed livestock, to maulings of hunters.

The best wildlife habitat in the state is now full of bears, forcing some of the animals to spill onto farms and residential areas, said Mark Bruscino, carnivore specialist with the Wyoming Game and Fish Department. He said the animals are now turning up in areas dominated by agriculture and with little cover for wildlife.

"We're dealing with bears that are in and around people constantly," Bruscino said. "There's no place to put them because the wildland habitat is full in our state."

Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

http://www.usatoday.com/travel/destinations/2010-11-02-yellowstone-grizzly-bears_N.htm

ursusarctos

 

Surface area to volume ratios for the finite element models of polar and brown bear skulls were similar, indicating that similar amounts of bone are used in the skulls of both species (SA/V: polar bear = 0.61, brown bear = 0.59). This finding suggests that differences in stress magnitudes between the polar bear and scaled brown bear skull models can be interpreted in light of differences in external shapes of the skulls. Bite forces measured from the two scaled finite element models were also comparable for all simulated bites, although the polar bear's bite was slightly stronger in each case (Table 2, Fig. 2a). These results suggest that the potential leverage of the jaw muscle systems is also similar for the two species.




Stress distributions and magnitudes differed between the two models for all bites. For each biting scenario, the polar bear skull exhibited more widely varying stresses (Fig. 3) and higher peak stresses (Table 3) than for the brown bear. Differences between the two species were most marked for bites made with the molars, where peak stresses in the polar bear were up to 408% those of the brown bear (Table 3). Similarly strain energy values were higher in the polar bear cranium than for the brown bear for all bites (Table 2; Fig. 2b), indicating that the polar bear skull undergoes more deformation in producing similar bite forces. Again, differences between the polar and brown bear crania were most pronounced for bites made with the post-canine dentition, the main site for processing of ingested food. Our model results are unvalidated by in vivo data and should be treated as estimates only. However, based on our findings, it appears that although the two species are similar in cranial size and have similar muscle leverage potential, the polar bear's skull is a weaker, less work-efficient structure, and does not appear well suited to dealing with large masticatory loads.




The transition to an arctic environment and hypercarnivorous diet resulted in extremely rapid morphological evolution in the polar bear lineage. Our results indicate that the rate of cranial shape evolution in the polar bear lineage was at least twice as fast as in other branches of ursid phylogeny. Our estimate is probably conservative; while the phylogeny that we used for rate estimates dates the polar bear/brown bear split at ~700 kya [3], recent analysis of sub-fossil polar bear remains suggests that polar bears diverged from brown bears as recently as 150 kya, and that the modern polar bear morphology was present by 130 kya [17]. Compared with other ursids, polar bears possess low flat skulls with elevated orbits [2], consistent with both semi-aquatic [18] and faunivorous [2] adaptations. This morphology might also increase hunting efficiency by allowing bears to thrust their heads into breathing holes or pupping dens. Polar bear evolution was facilitated by the expansion of polar ice sheets and floes in the late Pleistocene [19]. If polar bears evolved from coastal populations of brown bears [6], as molecular evidence now suggests [3]–[5], [17], then rapid evolution of adaptations for semi-aquatic life and hypercarnivory could have occurred to facilitate foraging over wider areas. Polar bears have denser fore- and hindlimb bones, a common adaptation of aquatic mammals, than closely related brown bears, further supporting this interpretation [20].

Although polar bears possess mechanically efficient skulls, as indicated by larger bite forces for a given muscle effort (Fig. 2A), we found that they also possess energetically inefficient and structurally weaker skulls (Fig. 2b; Fig. 3). This initially seems somewhat counterintuitive; among other carnivoran families, more carnivorous taxa tend to have stronger skulls [11], [13], [14]. However, polar bears feed almost exclusively on young ringed (Pusa hispida) and bearded (Erignatus barbatus) seals, which, at 68–250kg, are small prey in comparison to a ~500 kg adult polar bear [21], [22]. As a result, cranial reinforcement may not be necessary as in hypercarnivores such as lions or wolves that regularly take prey larger than themselves [11], [13], [14]. The performance of the polar bear skull is particularly poor during bites with the post-canine dentition. (Fig 2b; Fig 3b–d; f–h). Polar bears exhibit reduced premolars and molars in comparison with most other ursids [1] but also lack the well-developed shearing blade-like teeth of hypercarnivores [1], [23]. In this respect they parallel insectivorous carnivorans, such as aardwolf (Proteles cristata), bat-eared fox (Otocyon megalotis) and sloth bear (Ursus ursinus) [1], [2]. Although convergence between a carnivore and insectivores also appears surprising, consideration of food material properties sheds light on this finding. Polar bears feed as almost exclusively on blubber and flesh that, unlike bone, require little or no processing prior to swallowing. If there is no selective advantage to maintaining large molars, they can be rapidly lost through the action of a few small mutations [24] or simple developmental mechanisms [25], [26]. Brown bears, in contrast, are generalized omnivores with unreduced dentitions [1], [2]. Although they consume animal protein when available, brown bears seasonally consume large amounts of plant material, including grasses, which require extensive mechanical breakdown and repeated skull loading prior to swallowing [27]. This is reflected in their larger molar grinding area, similar to other omnivorous ursids [1]. The lower peak stresses and higher work efficiency of the the brown bear cranium may result in part from the species' deep, vaulted and pneumatized forehead (see Fig. 3), a morphology that is characteristic of all herbivorous and omnivorous ursids [2]. Although pneumatized spaces are associated with reduced structural strength of the cranium [28], their presence is also associated with dissipation of regular, large peak masticatory loads in bone-cracking hyaenas and fossil canids [29]–[32]. The low, flat head of the polar bear, while advantageous for its semi-aquatic lifestyle and hunting behavior, reduces the ability of the cranium to withstand repeated large loads generated by bites made with the post-canine dentition.

From Biomechanical Consequences of Rapid Evolution in the Polar Bear Lineage, by Graham J. Slater, Borja Figueirido, Leeann Louis, Paul Yang, and Blaire Van Valkenburgh.

taipan

 

Extinction Likely for World's Rarest Bear Subspecies

By John Platt | May 6, 2011 06:00 AM



The May 3 death of a Marsican brown bear (Ursus arctos marsicanus) has put the world's rarest bear subspecies one step closer to extinction. Just 50 or so of the animals remain in two of Italy's national parks, a population so small that the bears are "below the threshold of survival," Giuseppe Rossi, head of the National Park of Abruzzo, Lazio, and Molise, told The Christian Science Monitor.

The bear killed this week was likely struck by a car, an example of the increased bear-human conflict that has halved the population from 100 animals since the 1980s. In addition to traffic fatalities, poachers used poison to kill three bears in 2007, including a cub and his famous father named Bernardo, who was known for casually strolling around the streets of local villages. A female bear died in 2008, also from poisoning.

Although the bears have become people-friendly, that has put them even further at risk. As Italy magazine reported in 2008, some villagers "were unhappy with incursions by Bernardo and his kin, claiming they were a menace. The disappearance of high-mountain fodder and smallholdings has been one of the reasons why the bears have begun roaming further downhill, causing friction with humans."

Aiming to reduce this conflict, forest rangers have planted thousands of fruit trees in the parks over the last few years in hopes of increasing the bears' natural food supply. Last year, a $7.3 million project called Life Arctos (named after the bear) was launched, partially funded by the European Union, to coordinate conservation efforts between multiple government agencies and NGOs. According to The Christian Science Monitor, Life Arctos will help plant more trees and build electric fences around peoples' gardens and beehives to prevent bears from using human settlements as their grocery stores. According to the U.K.-based organization Save the Bears, the Marsican bears cause around $75,000 in damage every year to beehives, gardens and livestock.

http://www.scientificamerican.com/blog/post.cfm?id=extinction-likely-for-worlds-rarest-2011-05-06

ursusarctos

 

The highest kill rates were by male grizzlies killing cow moose during the calving period. We estimated that each adult male grizzly killed 3.3–3.9 adult moose annually, each female without cub(s) killed 0.6–0.8 adult moose and 0.9–1.0 adult caribou (Rangifer tarandus) annually, and each adult bear killed at least 5.4 moose calves annually.
From here.

Some info on muskox predation. It is also well known that grizzlies are successful predators of calves:

Although the above was mostly speculation (for reasons explained), what may be surprising is the amount of evidence of grizzlies making surplus kills of adults:





Here is the source.

hyaenidae

 

The often overlooked Himalayan and trans-Himalayan population:

[youtube]7aAWxkzywx0[/youtube]

ursusarctos

 

Info on the importance of social dominance on feeding ability of coastal brown bears from the article "The relative importance of prey density and social dominance in determining energy intake by bears feeding on Pacific salmon" by S.M. Gende and T.P. Quinn.

ursusarctos

 

From "Summer food habits of brown bears in Kekexili Nature Reserve, Qinghai-Tibetan Plateau, China" by Aichun, et al.

The authors stated they believe large mammal carcasses were scavenged.
It was nonetheless interesting that mammals made up 98% of the fecal dry weight in this population (or at least the sample of feces the authors examined).