taipan

 

"Black bears can injure or kill people, but they rarely do. When pressed, they usually retreat, even with cubs. Attacking to defend cubs is more a grizzly bear trait. (Grizzlies live only in Alaska, northern and western Canada, and the Rocky Mountains south to Yellowstone.) Black bear mothers often leave their cubs and flee from people, and those that remain are more likely to bluff-charge than attack. Still, it is prudent to use extra caution with family groups that allow close approaches because mothers are generally more nervous than other bears. Nevertheless, chances of being attacked around campsites by any black bear are small. During a 19-year study of bear/camper encounters in the Boundary Waters Canoe Area Wilderness in Minnesota, only two injuries were reported in 19 million visitor-days. The study included the year 1985 when bear nuisance activity was at a record high. The two injuries were by one bear on September 14 and 15, 1987. The bear was killed the next day.

Unprovoked, predatory attacks by black bears are rare but highly publicized. Such attacks have accounted for all 23 deaths by noncaptive black bears across North America this century. Most occurred in remote areas where the bears had little or no previous contact with people, rather than in and around established campsites. The worst attack occurred in Ontario in 1978 when a black bear killed and partially consumed three teenagers who were fishing. Predatory attacks by black bears are usually done without bluster or warning. People involved in such attacks can improve their chances by fighting rather than playing dead. Deaths from such attacks average a little more than one every four years across the United States and Canada."
http://www.ncrs.fs.fed.us/epubs/ht66.html

How does 1 black bear kill 3 presumably healthy teenagers?

pterodectyle

 

Home of the Rare White Spirit Bear

Not a Polar Bear, but an extreamly rare sub-species of the Black Bear.

Deal creates parkland for bears, wolves, salmon; Area home to rare white 'spirit' bear. Canada unveiled a 16-million acre preserve Tuesday, including parkland covering an area twice the size of Yellowstone, teeming with grizzly bears, wolves and wild salmon in the ancestral home of many native tribes. Closing another chapter of the wars between environmentalists and loggers, the Great Bear Rainforest is the result of an accord between governments, aboriginal First Nations, the logging industry and environmentalists. It will stretch 250 miles along British Columbia's rugged Pacific coastline -- the ancestral home of groups whose cultures date back thousands of years. The area also sustains a rare white bear which is found only in British Columbia. "The agreement on these areas represents an unprecedented collaboration between First Nations, industry, local governments and many other stakeholders in how we manage the vast richness of B.C.'s coast for the benefit of all British Columbians," said Premier Gordon Campbell, who was accompanied by native dancers and drummers for the announcement and formal First Nations blessing. "The result is a strong marriage that balances the needs of the environment with the need for sustainable jobs and a strong economic future for coastal communities," he said. Campbell said 4.4 million acres would be protected outright and managed as parkland, with another 11.6 million run under an ecosystem management plan to ensure sustainable forestry with minimal impact on the environment. Yellowstone National Park is 2.2 million acres. Full implementation of the project is not expected until 2009. British Columbia's lush evergreen forests have been the scene of decades of confrontation between environmentalists and loggers. Successful boycott campaigns in the 1990s led to large international companies turning away from British Columbia paper and wood products, forcing the government to find a negotiated solution. "British Columbians are showing that it is possible to protect the environment and provide the economic foundation for healthy communities," said Lisa Matthaus, coast campaign co-coordinator for the Sierra Club of Canada's British Columbia chapter. "This innovative rainforest agreement provides a real world example of how people and wilderness can prosper together." The region is home to hundreds of species, including grizzlies, black bears, the so-called spirit bear, wolves, cougars, mountain goats, moose and deer. The spirit bear is a rare white species and is also called the kermode bear. (Watch a rare spirit bear in Great Bear Rainforest -- 3:17) A central component of the Great Bear Rainforest project will be a $104 million conservation financing package to support the land-use agreements. To date, Greenpeace Canada, the Sierra Club of Canada and ForestEthics, the Nature Conservancy, Tides Canada Foundation and several private U.S. and Canadian foundations have raised $52 million to help establish the financing package. The provincial government has committed $26 million and project partners are working to secure the rest from Canada's federal government. Speaking on behalf of the 25 aboriginal groups involved in the project, Art Sterritt of the North Coast First Nations said the agreement would allow for controlled use of the land and let natives continue their traditional lifestyles. "It wasn't an easy job," he said. "Everyone had to make compromises here and there."

http://www.pandapaws.org/

pterodectyle

 

American black bear, (Ursus americanus)

The black bear is approximately 5 feet long and varies in weight from 125 to 400 pounds. It has small eyes, rounded ears, a long snout, a large body, and a short tail. The shaggy hair varies in color from white through chocolate brown, cinnamon brown, and blonde to black, but most black bears are indeed black or a darker shade of brown.

While black bears are capable of standing and walking on their hind legs, the usual posture is on all fours. The black bear's characteristic shuffle results from walking flat-footed, with the hind legs slightly longer than the front legs. Each paw has five strong, non-retractable claws used for tearing, digging, and climbing. One blow from a powerful front paw is enough to kill an adult deer. But in spite of their size and strength, black bears are surprisingly agile and careful in their movements.

Although much of its historical habitat has been destroyed by axe, plow, and bulldozer, the highly intelligent black bear has adapted and survived. Black bears are opportunistic feeders, making use of just about any available food source. While they prefer berries, nuts, grass, and other plants, they also eat carrion, small animals, and fish.

When fall approaches, black bears must eat large amounts of food in order to gain enough weight to sustain them through their winter hibernation, when they survive on their reserves of body fat. During periods of relatively warm weather, they may awaken and take short excursions outside.

Black bears reach breeding maturity at about 4 or 5 years of age, and breed every 2 to 3 years. Black bears breed in the spring, usually in May and June, but the embryos do not begin to develop until the mother dens in the fall to hibernate through the winter months. However, if food was scarce and the mother has not gained enough fat to sustain herself during hibernation as well as produce cubs, the embryos do not implant (develop).

Black bear cubs are generally born in January or February. The blind cubs weigh about « to 3/4 of a pound at birth, and twins are most common. By spring thaw, when the bears start leaving their dens, the cubs are fur-balls of energy, inquisitive and playful. They are weaned between July and September of their first year, and stay with the mother through the first full winter. They are usually independent by the second winter.

Cub survival is totally dependent on the skill of the mother in teaching her cubs what to eat, where and how to forage (find food), where to den, and when and where to seek shelter from heat or danger.

Except for breeding and raising young, black bears are generally solitary animals. They try to avoid humans and are considered non-aggressive except when injured, protecting their young, or protecting themselves. Daily movements are influenced greatly by temperature and food availability. Bears usually feed in the cool of the evening or early morning. During the heat of the day, they will seek shade in dense underbrush. Home ranges are determined by food types, abundance, and availability, and can be as small as 1 square mile or as great as 100 square miles.

Rugged terrain and dense shrubs provide escape cover and den sites for black bears. Black bears also seek den sites under fallen trees, in hollow trees or caves, or in previously occupied dens. They are excellent tree climbers, and will use trees to escape from danger. When possible, black bears will choose streams with dense bankside shrubbery as travel corridors to and from food sources.

The black bear's primary predator is man. During the American colonial period and after, black bears were hunted almost to extinction on the East Coast. Many states paid bounties for bears, and as late as 1977, there was still a bounty law on the books in Highland County, Virginia (even though it had been more than 30 years since the last bounty was paid).

In addition to the historical uncontrolled harvest encouraged by bounties, black bear numbers were reduced by timber harvesting and burning, clearing land for crops and grazing, and other encroachments associated with an expanding civilization. By the early 1900s, the once-numerous black bear could be found only in remote mountainous areas of Georgia, Kentucky, Maryland, North Carolina, Pennsylvania, Tennessee, Virginia, and West Virginia.

As small farms failed and people moved back to the cities, bear habitat slowly recovered and populations started to increase. The early establishment of national parks and national forests in the East helped save the black bear in that region.

Although attitudes concerning bears and other game animals were changing and wildlife laws protecting black bears and other animals were being enacted, the understanding of black bear biology, behavior, and habitat requirements remained incomplete. It wasn't until the 1960s that methods and techniques for safely trapping, immobilizing, and handling such powerful animals were developed. More has been learned about the habits and needs of the black bear in the last 30 years than in all of recorded history.

Thanks to this new knowledge and understanding, and better management, black bear populations have recovered significantly. However, they are not out of danger.

Today, a major threat to the American black bear is widespread poaching, or illegal killing, to supply Asian markets with bear gall bladders and paws, considered to have medicinal value in China, Japan, and Korea. The demand for these parts also affects grizzly and polar bears. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (also known as CITES), a treaty among more than 120 nations, provides measures to curb illegal trade in wildlife and wildlife products across international boundaries, helping to protect the black bear from poaching. The U.S. Fish and Wildlife Service is the agency responsible for the U.S. government's compliance with the CITES treaty.

Two subspecies found in the southeastern U.S., the Louisiana black bear and the Florida black bear, still face decline mainly due to habitat loss and degradation.

In 1992, the U.S. Fish and Wildlife Service listed the Louisiana black bear as a threatened species under the Endangered Species Act, meaning it could become in danger of extinction throughout all or a significant portion of its range in the foreseeable future. The American black bear also is protected by the Act in the affected states (Louisiana, Mississippi, and Texas) due to its close resemblance to this subspecies. The Florida black bear is a candidate for protection of the Endangered Species Act. The U.S. Fish and Wildlife Service monitors the animal's status and takes appropriate measures to ensure its conservation.

http://www.fws.gov/species/species_accounts/bio_bear.html

pterodectyle

 

huge male blackie weighing between 600 to 800 pounds - credited to big bons.



Black bear vs puma.

taipan

 

Hey Yogi! Bears' Picnic Basket Theft Secrets Revealed

By LiveScience Staff
posted: 06 May 2008 ET

A camper's worst nightmare has become a homeowner's reality for many: Bears that once rummaged around campsites now dive into suburban dumpsters and trash cans, munching on more than picnic snacks.

Many human-bear conflicts are caused by human food sources luring bears. Many more are caused by humans encroaching onto bear habitats.

In any case, scientists have wondered how animals learn to find and eat human food. Some researchers assumed bear cubs picked up this behavior from their mothers, but a new study may acquit mama bears.

Researchers found that black bears that steal human food are just as likely to form these habits on their own or pick them up from unrelated "bad influence" bears, as to learn them from their mothers. The scientists detailed their findings in the latest edition of the Journal of Mammalogy.

"Understanding how bears acquire behavior is important in conservation biology and devising strategies to minimize potential human-wildlife conflicts," said Wildlife Conservation Society (WCS) scientist Jon Beckmann, a co-author of the study. "According to our findings, bears that feed on human food and garbage are not always learning these habits from their mothers."

Distributed across much of North America, black bears — which average around 300 pounds in weight — become a problematic species for wildlife managers when they become accustomed to human sources of food, and the habit is a hard one to break. Bears that develop these tendencies often remain "problem" bears for human communities, leading to property damage, injuries to people, not to mention costly relocation and sometimes death for bears.

Working in the Lake Tahoe Basin on the California-Nevada border and California’s Yosemite National Park (where bears breaking into visitors' cars is commonplace), the researchers examined genetic and behavioral data for 116 black bears. The bears were classified as either food-conditioned (or hooked on human food) or non-food-conditioned (those bears that still forage on natural food sources). The study also focused on nine mother-offspring pairs to test the assumption that mother bears teach their cubs to invade garbage bins or homes.

The researchers found little evidence linking food-conditioned behavior to mother bears. Instead, it seems, bears may learn to seek out human food from other bears (not necessarily their relatives) or even just pick it up on their own, even without other bears around to set a bad example. More than half (five of nine) of the bears in the study had mothers who differed in behavior from them.

"These findings can help inform management strategies that would otherwise assume that cubs will always repeat the behaviors of food-conditioned mothers," said Jodi Hilty, director of WCS-North America. "Moving mothers and cubs may have only a limited effect in eliminating human-bear conflicts, which seem to be primarily driven by human food sources that are available to bears."

On the East Coast, WCS-Adirondacks has been supplying the High Peaks Wilderness Area in Upstate New York with bear-proof food canisters for campers to rent at local stores. A recent survey found that 95 percent of campers now use the canisters, and reports of conflicts between bears and campers have declined significantly.


Dumpster-diving bears are sometimes involved in conflicts with humans.

http://www.livescience.com/animals/080506-bad-bears.html

taipan

 

Black Bear Subspecies

taipan

 

Regarding the American Black Bear, the largest subspecies is the Queen Charlotte (Ursus Americanus Carlottae)

Some interesting info on there subspecies -
"Their reliance on forested habitat has greatly influenced their evolution; there is some evidence that black bears became separated into two lineages about 2 million years ago when the vast continental forest of North America became fragmented into a western and an eastern forest. Later at the beginning of the Pleistocene, the western lineage became separated into a coastal group and an interior group about 350,000 years ago.

The coastal group subsequently diverged into the four coastal subspecies:

• 
  
• Ursus Americanus kermodei,
  
• Ursus Americanus carlottae,
  
• Ursus Americanus vancouveri
  
• Ursus Americanus altifrontalis.
  

The interior group split to form:

• 
  
• Ursus Americanus cinnamomum
  
• Ursus Americanus americanus
  
  

The coastal subspecies may have been isolated on separate island refugia during the last Pleistocene glaciation. The subspecies carlottae is found on the Queen Charlotte Islands (Haida Gwai), while vancouveri is found on Vancouver Island. The subspecies kermodei, or the spirit bear, is found primarily on Princess Royal Island (see below) and may have survived the ice age on the westernmost part of this island in the Hecate Strait lowlands. Other possible refugia on the Northwest Pacific coast include the islands of Southeast Alaska (see the brown bear chapter), the Queen Charlotte Strait lowlands, the coastal fringe of mainland British Columbia, and western Washington. Of the 16 current black bear subspecies, 8 are likely to be found in British Columbia."
http://www.grizzlybear.org/bearbook/american_black_bear.htm[/size]

taipan

 

Urban Black Bears 'Live Fast, Die Young'

ScienceDaily (Oct. 1, 2008) — Black bears that live around urban areas weigh more, get pregnant at a younger age, and are more likely to die violent deaths, according to a study by the Wildlife Conservation Society (WCS).

The study, published in the Fall 2008 issue of the journal Human-Wildlife Conflicts, tracked 12 bears over a 10-year period living in urban areas around Lake Tahoe, Nevada and compared them to 10 "wildland" bears that lived in outlying wild areas. The authors found that bears in urbanized areas weighed an average of 30 percent more than bears in wild areas due to a diet heavily supplemented by garbage.

The authors believe that because the bears weigh more they are giving birth at an earlier age – on average when they are between 4-5 years old, as compared to 7-8 years for bears in wild areas. Some urban bears even reproduced as early as 2-3 years of age around Lake Tahoe.

Urban bears also tend to die much younger due mostly to collisions with vehicles, according to the study. All 12 urban bears tracked by the researcher were dead by age 10 due to vehicle collisions, while six of the wildland bears still survived. Bear cubs in urban areas also had dramatically higher mortality rates due mainly to vehicle collisions.

"Urban areas are becoming the ultimate bear traps," said Wildlife Conservation Society researcher Jon Beckmann, the study's lead author. "Because of an abundant food source – namely garbage – bears are being drawn in from backcountry areas into urbanized landscapes where they meet their demise."

The study warns that urbanized areas are functioning as "sinks" for black bear populations, drawing in bears from outlying wild areas, where they ultimately die. As a result, bears are failing to re-colonize outlying wild areas following this shift to urban centers.

The authors believe that without these sinks, populations of black bears in Nevada could increase. Right now, populations in Nevada remain steady due to bears immigrating from neighboring California. The Wildlife Conservation Society is studying the effects of urbanization and sprawl on a variety of wildlife and habitats in North America. WCS continues to work with local authorities to increase the use of bear-proof garbage containers and improve education efforts to reduce human-bear conflicts.


Wild black bear searching for food at a garbage dump. A life of garbage, early pregnancies and violent deaths plague big city bears.

http://www.sciencedaily.com/releases/2008/09/080930135301.htm

taipan

 

Spirit bears become 'invisible'

By Jody Bourton
Earth News reporter

Page last updated at 11:23 GMT, Friday, 6 November 2009


The benefits of being different

On a few islands in western Canada, white 'spirit bears' walk the woods.

Now scientists have discovered why these striking animals, a race of black bear, survive.

White bears are less visible to fish than their black counterparts, making them 30% more efficient at capturing salmon in the islands' rivers.

Elsewhere, similar white bears appear rarely, probably because those that do become vulnerable to predators such as grizzly bears and wolves.

The researchers have published their findings in the Biological Journal of the Linnean Society.

Most black bears (Ursus americanus) in North America have a coat that is uniformly black.

That provides camouflage within the forest habitats in which most bears live.

However, the spirit bear, also known as the kermode bear (Ursus americanus kermodei), is a race of black bear that has a white coat.

The white fur is produced by a recessive form of a gene, or allele, that maintains itself in the black bear gene pool. This is much like how red hair occurs in humans.

This race of white bear has a restricted distribution, occurring mainly on Gribbell Island and Princess Royal Island off the coast of western Canada, 500 km north of Vancouver.

"The spirit bear is a total oddball," says Dr Thomas Reimchen from the University of Victoria in British Columbia, Canada.

White black bears hardly ever appear in the general population.

Yet "here on these two small islands you suddenly get 20-30% of the bear being white," says Dr Reimchen, who studied the animals with colleague Mr Dan Klinka.

Invisible bears

Rather than make the bears stand out, the white colour actually makes the bears disappear, the researchers discovered.

Each autumn, salmon fill the islands' rivers as they migrate to their spawning grounds.

At night, black bears and white bears have similar rates of success at capturing salmon.

But the white bears come into their own during the day.

"In the daytime the white bear is 30% more efficient than a black bear in capturing salmon," says Dr Reimchen.

The two researchers made the discovery by observing the hunting techniques of the two types of wild black bear, including bears stalking, lunging for and running after salmon.

"The white bear was more successful in any one of those techniques during the daytime compared to the black bear," he says.

They also conducted experiments on the reaction of the salmon.

By draping themselves in white and black costumes, they confirmed that salmon try to evade white coloured objects far less than black.

"We hadn't expected such a clear result as we got with our experimental work," Dr Reimchen says.

"The salmon were twice as likely to return to the area with the white costume than the dark costume."

The scientists believe that the white bears' lighter colour makes them less visible to salmon in daytime, and that dark coloured predators are more easily spotted against the bright surface of the water.

Visible to some

That hunting prowess gives white bears a distinct advantage, with the salmon protein helping them better fatten up for the winter, and successfully raise young.

But if white coats are better, why don't white bears exist in large numbers elsewhere among the black bear population?

Researchers suspect the coat makes white bears more vulnerable to other predators, which do not exist on Gribbell Island and Princess Royal Island.

"Probably one of the reasons they are not common on the mainland is grizzly bears kill black bears and wolves kill black bears," Dr Reimchen says.

"The white bear may simply be at a disadvantage by nature of its visibility."

It might also be that the genetic mutation that causes the white coat exists on these islands and nowhere else, and it persists because the bears are isolated.

The first nation Tsimshian people have a legend that the bear is a relic from a glacial age where it would be suited.

This is consistent with recent research that suggests coastal bears survived through glacial periods.

Disappear for good

The spirit bears' future survival is not guaranteed, however.

Isotope analyses of the bears' hair shows what they eat, and a study by the researchers reveals that white bears are much more dependent on salmon than their black counterparts.

But overfishing and habitat destruction have caused a dramatic decline in salmon numbers along the west coast of North America over the past 100 years.

"I would be dubious if the white bears persist when their salmon disappear, and they are almost gone already," says Dr Reimchen.

"These bears do not have an opportunity to switch to anything else."

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8344000/8344367.stm

scottwolverine1111

 

ursusarctos

 

A northern Minnesota black bear has survived for an amazing 36 years, making her one of the oldest on record.
The bear is simply called No. 56, but "Lucky" might be a better name.

The northern Minnesota black bear has beaten long odds, living to a ripe old age of 36 -- one of the oldest -- if not the oldest, wild black bears on record.

She was first caught and outfitted with a radio collar in 1981, when she was 7. Since then, she's survived 29 hunting seasons and avoided cars on highways and clashes with rural residents.

How rare is she?

The average age of a bear killed by a hunter in Minnesota is 3.7 years old. About 80 percent of her 26 cubs died by age 6. And the oldest bear ever killed here by a hunter was 31, based on 35 years of data using teeth to determine the age of harvested bears.

"Obviously she's really a special bear," said Department of Natural Resources research biologist Karen Noyce of Grand Rapids, who has been monitoring No. 56 since she first tranquilized and attached a radio collar to the bear back in 1981.

Of the hundreds of bears that have been radio collared since then, the longest that any survived was 23 years, Noyce said.

"Very few bears live past 25," said Dave Garshelis, DNR bear research scientist. "This is really old for a wild bear. She has found a way to beat the odds."

Cautious by nature

But Noyce and Garshelis say there's probably a reason, beyond chance or luck, for her longevity.

"It has to be something behavioral," Garshelis said. "She has avoided going to hunters' baits, though there are hunters where she lives. Whether she learned early in life from her mother ... we just don't know."

Said Noyce: "Some of that might be her personality; she might have a somewhat more cautious nature than other bears."

People assume a bear is a bear, but Noyce said studies of many animals are showing that they can be quite different. Bears don't all act the same. A bold or reckless one might not last long.

No. 56 -- called that because of the numbered tag she was given -- lives in a remote area without a lot of permanent human residences. But there are roads, trails and access by hunters, who typically place bait in the woods to attract bears each fall.

But for whatever reason, she has ignored them.

And she's apparently passed on that sense of caution to her offspring.

Noyce said No. 56 had at least 26 cubs. All but three survived the first year and one-third survived to age 4.

"That's a little better than average," Noyce said.

One of her cubs lived 16 years, another is still alive at 15. At least five of her cubs bore another 47 "grandchildren," and one of those lived 22 years and bore 28 great-grandchildren. Researchers only tracked the female cubs, so that doesn't account for reproduction from male descendents. The bear was 26 years old when she had her last litter of cubs.

She also could have encountered trouble during her summer wanderings. It's not uncommon for bears to leave their home range and travel in mid-summer in search of food, and No. 56 did quite a bit of traveling in the 10 years her movement was closely monitored. Her home range covers about 15 square miles, but one year she traveled 45 miles away and another year she covered 20 miles.

Researchers have visited No. 56 in person every three years, when Noyce replaces the radio collar with a new one. Noyce, Garshelis and Ken Soring, a former DNR researcher and now DNR enforcement manager who helped collar the bear in 1981, recently went into the woods to find the old gal.

Wanted: A natural death

They tranquilized her while she was hibernating in her den, checked her health and attached a new radio collar.

"She's healthy," said Noyce. She weighs about 190 pounds. Her face and paws are gray with age. And her teeth are worn, chipped or missing. And that could affect her chances of survival.

"If she has trouble eating natural foods, she may be more attracted to some other food source," Garshelis said. Like a bait pile.



Number 56 at the age 7, back in 1981:


At 36, her graying paws:

And teeth:


Full respect for her-she was an amazingly successful bear, and I wish her the best.
Nearly 10 times older than the average.

Thanks go to Warsaw for finding the article.

taipan

 

Bears Uncouple Temperature and Metabolism for Hibernation, New Study Shows

ScienceDaily (Feb. 17, 2011) — Several American black bears, captured by the Alaska Department of Fish and Game after wandering a bit too close to human communities, have given researchers the opportunity to study hibernation in these large mammals like never before. Surprisingly, the new findings show that although black bears only reduce their body temperatures slightly during hibernation, their metabolic activity drops dramatically, slowing to about 25 percent of their normal, active rates.

This discovery was unexpected because, generally, an organism's chemical and biological processes are known to slow by approximately 50 percent for each 10 degree (Celsius) drop in body temperature. These Alaskan black bears only lowered their core body temperatures by five or six degrees, yet their metabolism slowed to rates much lower than researchers had imagined.

Furthermore, the black bears' metabolism remained significantly suppressed for several weeks after the animals emerged from their slumber.

Øivind Tøien and a group from the Institute of Arctic Biology at the University of Alaska Fairbanks, along with colleagues from Stanford University, will report their findings at the 2011 AAAS Annual Meeting in Washington, DC, on 17 February. Their study will also appear in the 18 February issue of Science.

Their study is the first to continuously measure the metabolic rates and body temperatures of black bears, or Ursus americanus, as they hibernated through the winter under natural conditions. The bears spend five to seven months without eating, drinking, urinating or defecating before they emerge from their dens in nearly the same physiological condition they were in when they entered them. This feat leads researchers to believe that, in the future, the data collected in this study might be applied to a very wide range of endeavors -- from improving medical care to pioneering deep space travel.

The black, furry study participants, who had been deemed nuisance bears by the Alaska Department of Fish and Game, were transported to the Institute of Arctic Biology where they were placed in structures designed to mimic a bear's den. These dens were located in the woods, away from human disturbances, and equipped with infrared cameras, activity detectors and other remote sensing devices. Tøien and his colleagues also implanted radio transmitters into each bear to record the animals' body temperatures, heart beats and muscle activity.

By monitoring the black bears, day and night for five months of hibernation, the researchers observed that the bears' body temperatures fluctuated between 30 and 36 degrees Celsius in slow two- to seven-day cycles. Such large, multi-day fluctuations in core body temperature are unlike those observed in any other hibernators before.

One female black bear that was pregnant during her hibernation maintained a normal, wakeful body temperature throughout the pregnancy -- a detail that implies fluctuating temperature cycles may not be favorable for embryonic development. After she birthed her cub (who unfortunately died due to a congenital diaphragmatic hernia), the female bear's body temperature began to fall and it eventually joined the variable cycle that the other hibernating bears experienced.

"A very important clue to understand what is going on with the bear's metabolism is their body temperatures," Tøien said. "We knew that bears decreased their body temperatures to some degree during hibernation, but in Alaska we found that these black bears regulate their core temperature in variable cycles over a period of many days, which is not seen in smaller hibernators and which we are not aware has been seen in mammals at all before."

Once the bears' core body temperatures dropped to about 30 degrees Celsius, they were observed to shiver until their temperatures reached about 36 degrees Celsius, which often took several days. Then the bears reduced shivering until their body temperature again fell to about 30 degrees Celsius, and the cycle began again.

By measuring how much oxygen the creatures consumed while hibernating in the mock dens, the researchers could glean that the bears reduced their metabolic rates by 75 percent compared to their summertime levels. The animals' heart rates also slowed from around 55 beats per minute to about 14 beats per minute.

"Sinus arrhythmia is a variation in heartbeat frequency relative to breathing, and the bears show an extreme form of this," said Tøien. "They have an almost-normal heartbeat when they take a breath. But, between breaths, the bears' hearts beat very slowly. Sometimes, there is as much as 20 seconds between beats. Each time the bear takes a breath its heart accelerates for a short time to almost that of a resting bear in summer. When the bear breathes out, the heart slows down again…"

In spring, when the bears awoke and emerged from their dens, the researchers had expected to find the animals' metabolism returning to normal levels right away. But, the team was again surprised to find that the bears' metabolic rates were still only half of their normal, summer levels. Tøien and his team continued to monitor the bears' metabolism for another month after their hibernation and determined that the bears did not return to their active metabolic activity for two to three full weeks.

Taken together, these findings paint a unique picture of hibernation in a human-sized mammal -- and researchers hope to apply them in a wide range of disciplines. Since some form of hibernation -- in which body temperature and metabolism are reduced -- has been observed in nine orders of mammals, it is likely that the genetic basis for this ability is ancient and widespread and that it could be exploited for various purposes. "If our research could help by showing how to reduce metabolic rates and oxygen demands in human tissues, one could possibly save people," Tøien said. "We simply need to learn how to turn things on and off to induce states that take advantage of the different levels of hibernation."

"When black bears emerge from hibernation in spring, it has been shown that they have not suffered the losses in muscle and bone mass and function that would be expected to occur in humans over such a long time of immobility and disuse," continued Brian Barnes, the senior author of the study. "If we could discover the genetic and molecular basis for this protection, and for the mechanisms that underlie the reduction in metabolic demand, there is the possibility that we could derive new therapies and medicines to use on humans to prevent osteoporosis, disuse atrophy of muscle, or even to place injured people in a type of suspended or reduced animation until they can be delivered to advanced medical care -- extending the golden hour to a golden day or a golden week."

Hibernation could also become relevant for deep space travel, researchers say. If the human race is ever able to leave Earth as a species, it might be necessary to induce a bear-like hibernation in order to make the trip into deep space possible.

Of course, these possibilities will require much more research in order to achieve them.

This report by Tøien et al. was funded by a U.S. Army Medical Research and Materiel Command grant, grants from the National Science Foundation, a grant from the National Institutes of Health, gift funds to Stanford University, the American Heart Association and the Fulbright Program.


Black bears show surprisingly large and previously unobserved decreases in their metabolism during and after hibernation.

--------------------------------------------------------------------------------

Journal Reference:

Gerhard Heldmaier. Life on Low Flame in Hibernation. Science, February 17, 2011; Vol. 331 no. 6019 pp. 866-867 DOI: [url]10.1126/science.1203192[/url]

http://www.sciencedaily.com/releases/2011/02/110217141311.htm

taipan

 

Don't blame mother: study says male black bears more likely to kill

By Bill Graveland, The Canadian Press – 26 minutes ago

CALGARY — Mother black bears may be getting a bad rap.

Research suggests that the traditional perception of female bears fatally attacking humans to protect cubs is wrong. In reality, the vast majority of deadly encounters are with male black bears on the hunt.

"One of the surprises was that the females that can act so aggressively when they feel threatened are really not the ones that follow through with the serious stuff," said Stephen Herrero, an expert in bear behaviour and ecology at the University of Calgary. "The male bears are the ones that follow through with the serious stuff."

Herrero worked with graduate student Andrew Higgins, Brigham Young University in Utah and colleagues from the Massachusetts division of Fisheries and Wildlife to analyze recorded deaths caused by non-captive black bears in North America between 1900 and 2009.

Fatal maulings are actually quite rare. Only 63 people were killed in Canada and the United States during that time. In Canada, there have been a handful of fatal attacks in the last five years.

The research, which is published in the Journal of Wildlife Management, concluded that the majority of fatal encounters involved bears exhibiting predatory behaviour and 92 per cent of those bears were males.

Herrero said there are two distinct kinds of behaviour that bears exhibit and there's a reason that females with cubs tend to get the blame.

"It's because of the way they act. They blow. They snort. They swat the ground. They run at you. They make it look like they're going to eat you alive and that's exactly what they want (you to think)," he said.

"They want to get their way without really mixing it up and where they might get injured."

But the male's approach is different.

"The predatory male bear is like any predatory animal. It's silent. It's stalking and then makes a rush at a person," Herrero explained.

"Male bears simply take more risks in order to get the resources that they need to be able to breed with females. They're more willing to prey on potentially dangerous animals like elk or moose.

"The males simply are pushed a little bit more than the females by their evolutionary mandate to be big and strong."

There are about 900,000 black bears in North America.

Herrero said the black bear may not be as physically intimidating as the much-larger grizzly but is usually strong enough to overpower most people.

He advises that the last thing anyone should do if being stalked by a bear is to run for it.

"If you see that bear constantly following you, that's the time for you and your friends to stop and act aggressively to the bear. You shout. You throw things at it. You take runs at it."

Herrero is the author of "Bear Attacks: Their Causes and Avoidance," which has sold over 125,000 copies worldwide.

His past research on bear attacks has helped develop new policies on bear safety and shifted focus to bear conservation.

http://www.google.com/hostednews/canadianpress/article/ALeqM5jaCizUbjzxLStUBYDPSP9ERiOaVg?docId=6812364

taipan

 

Fast Asleep to Wide Awake: Hibernating Bears, Predation and Pregnancy

ScienceDaily (Aug. 25, 2011) — Black bears hibernate, sleeping their way through winter, and who can blame them? But science is only just beginning to understand the physiological changes that allow bears to re-emerge in spring without much muscle and bone loss, and how they escape from danger during the colder months. New research published in BioMed Central's open access journal BMC Physiology used cardiac monitors and radio collars to measure the year round changes in heart rate and activity of wild black bears.

Previous studies have shown that during hibernation black bears undergo extreme variations in heart rate (respiratory sinus arrhythmia) -- the bear's heart rate increases when it takes a breath but stops for extended periods between breaths. In this study the researchers were able to monitor wild American black bears (Ursus americanus) throughout the year, 24 hours a day. They found that the bears had a pronounced respiratory sinus arrhythmia during hibernation and in the months leading up to their winter sleep. In addition, the bears were less active during the day in autumn, switching to being nocturnal. During the summer months, bears were active for up to 18 hours per day and had peak heart rates of over 200 beats per minute, however, during hibernation, respiration rates were as low as two breaths per minute and gaps of over 14 seconds without a heartbeat were recorded.

Pregnant wild bears hibernated deeply at the beginning of winter but their heart rates increased as their pregnancy continued, spiking during birth. After the cubs were born their mother's heart rate returned to hibernation levels. For several weeks after giving birth the mothers also exhibited much less movement, preventing accidental damage to the suckling cubs.

Dr Timothy Laske, one of the team who performed the research said, "When we retrieved our data, even though we tried to be as quiet as possible, the bears' heart rates increased before we reached the entrance to their winter den and remained elevated for a number of days. This confirms that despite apparent deep sleep, bears are always alert to danger and ready to act."

Dr David Garshelis who collaborated on this project continued, "Using this technology, year-round monitoring of wild bears allows us to observe details of bear behavior, such as pregnancy and birth, or interactions between bears and other wild animals, without disturbing their natural behavior." Dr Laske added, "Black bears often make their way into suburban areas which can be dangerous and stressful for both bears and humans and understanding the silent effect of humans and the environment on bears will also allow better bear management."


Hibernating bear with cubs born earlier in the winter. After the cubs were born their mother’s heart rate returned to hibernation levels. For several weeks after giving birth the mothers also exhibited much less movement, preventing accidental damage to the suckling cubs.

--------------------------------------------------------------------------------

Journal Reference:

Timothy G. Laske, David L. Garshelis, Paul A. Iaizzo. Monitoring the wild black bear's reaction to human and environmental stressors. BMC Physiology, 2011; DOI: [url]10.1186/1472-6793-11-13[/url]

http://www.sciencedaily.com/releases/2011/08/110817022136.htm

Ursus arctos

Jan 10 2012, 11:24 PM

A northern Minnesota black bear has survived for an amazing 36 years, making her one of the oldest on record.
The bear is simply called No. 56, but "Lucky" might be a better name.

The northern Minnesota black bear has beaten long odds, living to a ripe old age of 36 -- one of the oldest -- if not the oldest, wild black bears on record.

She was first caught and outfitted with a radio collar in 1981, when she was 7. Since then, she's survived 29 hunting seasons and avoided cars on highways and clashes with rural residents.

How rare is she?

The average age of a bear killed by a hunter in Minnesota is 3.7 years old. About 80 percent of her 26 cubs died by age 6. And the oldest bear ever killed here by a hunter was 31, based on 35 years of data using teeth to determine the age of harvested bears.

"Obviously she's really a special bear," said Department of Natural Resources research biologist Karen Noyce of Grand Rapids, who has been monitoring No. 56 since she first tranquilized and attached a radio collar to the bear back in 1981.

Of the hundreds of bears that have been radio collared since then, the longest that any survived was 23 years, Noyce said.

"Very few bears live past 25," said Dave Garshelis, DNR bear research scientist. "This is really old for a wild bear. She has found a way to beat the odds."

Cautious by nature

But Noyce and Garshelis say there's probably a reason, beyond chance or luck, for her longevity.

"It has to be something behavioral," Garshelis said. "She has avoided going to hunters' baits, though there are hunters where she lives. Whether she learned early in life from her mother ... we just don't know."

Said Noyce: "Some of that might be her personality; she might have a somewhat more cautious nature than other bears."

People assume a bear is a bear, but Noyce said studies of many animals are showing that they can be quite different. Bears don't all act the same. A bold or reckless one might not last long.

No. 56 -- called that because of the numbered tag she was given -- lives in a remote area without a lot of permanent human residences. But there are roads, trails and access by hunters, who typically place bait in the woods to attract bears each fall.

But for whatever reason, she has ignored them.

And she's apparently passed on that sense of caution to her offspring.

Noyce said No. 56 had at least 26 cubs. All but three survived the first year and one-third survived to age 4.

"That's a little better than average," Noyce said.

One of her cubs lived 16 years, another is still alive at 15. At least five of her cubs bore another 47 "grandchildren," and one of those lived 22 years and bore 28 great-grandchildren. Researchers only tracked the female cubs, so that doesn't account for reproduction from male descendents. The bear was 26 years old when she had her last litter of cubs.

She also could have encountered trouble during her summer wanderings. It's not uncommon for bears to leave their home range and travel in mid-summer in search of food, and No. 56 did quite a bit of traveling in the 10 years her movement was closely monitored. Her home range covers about 15 square miles, but one year she traveled 45 miles away and another year she covered 20 miles.

Researchers have visited No. 56 in person every three years, when Noyce replaces the radio collar with a new one. Noyce, Garshelis and Ken Soring, a former DNR researcher and now DNR enforcement manager who helped collar the bear in 1981, recently went into the woods to find the old gal.

Wanted: A natural death

They tranquilized her while she was hibernating in her den, checked her health and attached a new radio collar.

"She's healthy," said Noyce. She weighs about 190 pounds. Her face and paws are gray with age. And her teeth are worn, chipped or missing. And that could affect her chances of survival.

"If she has trouble eating natural foods, she may be more attracted to some other food source," Garshelis said. Like a bait pile.



Number 56 at the age 7, back in 1981:


At 36, her graying paws:

And teeth:


Full respect for her-she was an amazingly successful bear, and I wish her the best.
Nearly 10 times older than the average.

Thanks go to Warsaw for finding the article.

Ursus arctos

Jul 5 2013, 09:51 AM

She's still alive! Poor girl doesn't seem to be doing that well now though.