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|Sperm whale - Physeter macrocephalus|
|Topic Started: Jan 9 2012, 12:26 PM (2,352 Views)|
|Taipan||Jan 9 2012, 12:26 PM Post #1|
Sperm Whale - Physeter macrocephalus
Conservation status: Vulnerable
Species: P. macrocephalus
The Sperm Whale (Physeter macrocephalus) is the largest of all toothed whales and is the largest toothed animal alive, measuring up to 18 metres (60 ft) long. The whale was named after the milky-white substance spermaceti found in its head and originally mistaken for sperm. The Sperm Whale's enormous head and distinctive shape, as well as its central role in Herman Melville's Moby-thingy, have led many to describe it as the archetypal whale. Partly due to Melville, the Sperm Whale is commonly associated with the mythological Leviathan of the Bible.
Historically the Sperm Whale has also been known as the Common Cachalot. The word cachalot is originally Portuguese (cachalote), probably coming from cachola, a colloquial term for head. Sperm Whales were hunted until recently in the Portuguese atlantic archipelago of Azores. The Sperm Whale is also the state animal of Connecticut.
The Sperm Whale is exceptional for its very large head, particularly in males, which is typically one-third of the animals' length. Indeed, the species name macrocephalus is derived from the Greek for "big head" (strictly: long head). In contrast to the smooth skin of most other large whales, the skin on the back of the Sperm Whale is usually knobbly and has been likened to a prune by whale-watching enthusiasts . They are uniformly grey in colour though may appear brown in sunlight (the "Great White Whale" of Melville's novel, if such an animal existed, was an albino, and white sperm whales have been reported in reality as well). Perhaps unsurprisingly, the brain of the Sperm Whale is the largest and heaviest known of any modern or extinct animal (weighing on average 7 kg (15 lb) in a grown male). However, the brain is not large relative to body size.
The blowhole is situated very close to the front of the head and shifted to the whale's left. This gives rise to a distinctive bushy blow angled forward. The dorsal fin is set about two-thirds of the way down the spine and is typically short and shaped like an equilateral triangle.
Sperm Whales have 20–26 pairs of cone-shaped teeth in their lower jaw. each 8-20 cm (3-8 in) long. Each tooth can weigh as much as one kilogram. The reason for the existence of the teeth is not known with certainty. It is believed that they are not necessary for feeding on squid (see Feeding below) and indeed healthy well-fed Sperm Whales have been found in the wild without teeth. The current scientific consensus is that the teeth may be used for aggression between males of the same species. This hypothesis is consistent with the conic shape and wide spacing of the teeth. Rudimentary teeth are also present in the upper jaw, but these rarely open into the mouth.
Sperm Whales are amongst the most sexually dimorphic (that is, males and females differ greatly) of all cetaceans. Males are typically 30%–50% longer (16–18 m, 52-59 ft) than females (12–14 m, 39-46 ft) and weigh about twice as much (50,000 kg vs. 25,000 kg, 55 short tons vs 27.5 short tons). At birth both males and females are about 4 m (13 feet) in length and 1,000 kg (1 tonne) in weight. Due to extensive whaling, Sperm Whale size has decreased dramatically, mostly because the largest males were killed first and most intensively, for they had more spermaceti (spermaceti oil was of great value in the 18th and 19th century - see below). In a Nantucket museum there is a jawbone of a sperm whale which is 5.5 m (18 ft). The jawbone makes up to 20%-25% of the sperm whale's overall body length. Thus this whale might have been 28 m (90 ft) long, weighing around 150 metric tons (165 short tons). Another evidence of large bulls of the past resides in New Bedford museum, a 5.2 metres (17 feet) jaw of a bull that could have been about 25.6 metres (84 feet) long, weighing about 120-130 tons. In addition, log books found in the Nantucket and Bedford museums are filled with references to bulls that were, considering the amount of oil they yielded, about the same size as these two examples. Today, Sperm Whale males do not usually exceed 18 m (60 feet) in length and 52 metric tons (57 short tons) in weight.
In 1820, a sperm whale estimated to be about 25.9 m (85 ft) long attacked a Nantucket whaling ship Essex. Only 8 out of the 20 sailors managed to survive and be rescued by other ships.
Sperm Whales are a prime example of a species that has been K-selected, which is to say that the species is believed to have developed primarily under very stable environmental conditions. This relatively "easy" evolution has led them to have a low birth rate, slow maturation and high longevity. Females give birth once every four to six years, and the gestation period is at least 12 months and possibly as long as 18 months. Nursing takes place for two to three years. In males, puberty lasts for about ten years between the ages of about 10 and 20. Males continue to grow into their 30s and 40s and only reach their full size when about 50 years old. Sperm Whales live for up to 80 years.
The Sperm Whale holds some absolute world records:
Largest known toothed mammal ever.
Deepest dive by a mammal (sperm whales have been found in depths of 2,200 metres (7,200 feet), tangled in telegraph cables).
Largest brain of any living creature on Earth. The brain of a mature sperm whale weighs 7 kg (15 pounds), though there have been specimens with 9 kg (20 pound) brains.
Thickest skin. On back and head, sperm whale's skin (not including subcutaneous fat) is sometimes up to 35 centimetres (14 inches) thick.
According to a 2003 National Geographic article, Sperm Whales are said to be the loudest of all animals ("about as loud as a rifle shot three feet from your ear").
The Sperm Whale was categorized first by Linnaeus in 1758 who recognised four species in the Physeter genus. Experts soon realised that just one such species exists. In most modern publications the Sperm Whale is classified as the sole species in the family Physeteridae (and thus the only species in its genus). The sperm whale family is sometimes treated as a superfamily, Physeteroidea. This superfamily contains only two other species—the Pygmy Sperm Whale and the Dwarf Sperm Whale. These two whales belong to the family Kogiidae.
Mead and Brownell (1993), however, list all three species in the family Kogiidae, give the Sperm Whale the binomial name Physeter catodon and dispense with the superfamily.
The following is an extract from Melville's Moby-thingy, in which he expatiates about the naming and common lore surrounding the Sperm Whale:
"This whale, among the English of old vaguely known as Trumpa whale, and the Physeter whale, and the Anvil Headed whale, is the present Cachalot of the French, the Pottfisch of the Germans, and the Macrocephalus of the Long Words. [text omitted] It is chiefly with his name that I now have to do. Philologically considered, it is absurd. Some centuries ago, when the Sperm whale was almost wholly unknown in his proper individuality, and when his oil was only accidentally obtained from the stranded fish; in those days spermaceti, it would seem, was popularly supposed to be derived from a creature identical with the one then known in England as the Greenland or Right Whale. It was the idea also, that this same spermaceti was that quickening humor of the Greenland Whale which the first syllable of the word literally expresses. In those times, also, spermaceti was exceedingly scarce, not being used for light, but only as an ointment and medicament. It was only to be had from the druggists as you nowadays buy an ounce of rhubarb. When, as I opine, in the course of time, the true nature of spermaceti became known, its original name was still retained by the dealers; no doubt to enhance its value by a notion so strangely significant of its scarcity. And so the appellation must at last have come to be bestowed upon the whale from which this spermaceti was really derived." [from Melville's Moby thingy, Chapter 32, named "Cetology"]
Sperm Whales are believed to have diverged from other toothed whales early in the evolution of the suborder—around twenty million years ago .
The precise function of spermaceti and the organs it fills is not known, but at least three (not necessarily mutually exclusive) hypotheses exist:
One hypothesis, incidentally discussed in Moby-thingy by Melville, is that the case evolved as a kind of battering ram for use in fights between males. This hypothesis is consistent with the well-documented sinking of the ships Essex and Ann Alexander due to attacks by Sperm Whales estimated to weigh only one-fifth as much as the ships.
A second, more long-standing suggestion is that the case is an aid to the whale in controlling buoyancy. The density of the wax could be increased by cooling it with water brought in through the blowhole, helping the whale to sink. Conversely, forcing water out through the blowhole again would cause the spermaceti to reheat, become less dense and aid floating. This popularly quoted theory has recently lost some credence. Research suggests that no capillary effect would be extensive enough to change drastically the buoyancy of a 50-tonne whale.
A third possibility is that the case is used as an aid to echolocation, see melon. The shape of the organ at any given time is likely to focus or widen the beam of emitted sound. The sound waves may be so focused that they act as a kind of stun gun, temporarily disabling prey. Active research into all these possibilities continues.
Spermaceti was much sought after by 18th-, 19th- and 20th-century whalers. The substance found a variety of commercial applications, such as watch oil, automatic transmission fluid, lubricant for delicate high-altitude instruments, cosmetics, additives in motor oils, glycerine, rust-proofing compounds, detergent, chemical fibres, vitamins and 70 or more pharmaceutical compounds.
Feeding, behaviour and diving
A piece of Sperm Whale skin with giant squid sucker scarsSperm Whales, along with bottlenose whales, are the deepest-diving mammals in the world. They are believed to be able to dive up to 3,000 metres in depth and 2 hours in duration to the ocean floor. More typical dives are around 400 metres in depth and 30–45 minutes' duration. They feed on several species, in particular giant squid, octopuses and demersal rays. Almost all that is known about deep sea squid has been learned from specimens found in captured Sperm Whale stomachs. Stories about titanic battles between Sperm Whales and giant squid which are believed to reach up to 13 m (44 ft) are perhaps the stuff of legend. However, white scars on the bodies of Sperm Whales are believed to be caused by squid. It is also hypothesised that the sharp beak of a consumed squid lodged in the whale's intestine leads to the production of ambergris, analogous to the production of pearls. Sperm Whales are prodigious feeders and eat around 3% of their body weight per day. The total annual consumption of prey by Sperm Whales worldwide is estimated to be about 100 million tons — a figure greater than the total consumption of marine animals by humans each year.
The only predator that attacks sperm whales, besides man, is the orca. Large, roving pods of orcas frequently target groups of females with young, usually trying to separate the sperm whale calf and kill it. Oftentimes, the female sperm whales can repel these attacks by forming a circle with their calves in the center and then violently thrashing their tail flukes, so that no orca can penetrate the formation. If the orca pod is extremely large, they may sometimes also kill adult females. Large bull sperm whale have no predators, as even orcas could be killed by these aggressive, powerful creatures.
In addition, long-line fishing operations in the Gulf of Alaska have complained that numerous Sperm Whales have taken advantage of their fishing operations to eat desirable species straight off the line, sparing the whales the need to hunt them themselves
The physiology of the Sperm Whale has several adaptations to cope with drastic changes in pressure when diving. The ribcage is flexible to allow lung collapse, and the heart rate can decrease to preserve oxygen supplies. Myoglobin stores oxygen in muscle tissue. Blood can be directed towards the brain and other essential organs only, when oxygen levels deplete. The spermaceti organ may also play a role (see above).
While sperm whales are well adapted to diving, repeated dives to great depths do have long term effects on the whales. Skeletons of sperm whales show pitting of the bones that is often a sign of decompression sickness in humans. Skeletons of the oldest whales showed the most extensive pitting, whereas skeletons of sperm whale calves showed no damage. This damage may indicate that sperm whales are susceptible to decompression sickness, and sudden surfacing could be lethal to them.
Between dives, the Sperm Whale will come up to the surface for breath and remain more or less still for eight to ten minutes before diving again.
Because of the great depths to which they dive, Sperm Whales sometimes drown when entangled in transoceanic telephone cables.
The social structure of the Sperm Whales species divides on sexual lines. Females are extremely social animals, a trait believed to derive from their relatively simple evolutionary path. Females stay in groups of about a dozen individuals and their young. Males leave these "nursery schools" at somewhere between 4 and 21 years of age and join a "bachelor school" with other males of a similar age and size. As males grow older, they tend to disperse into smaller groups, and the oldest males typically live solitary lives. Yet mature males have been stranded on beaches together, suggesting a degree of co-operation not yet fully understood.
The Sperm Whale is among the most cosmopolitan species in the world, and is found in all the oceans and the Mediterranean Sea. The species is relatively abundant from arctic waters to the equator. Populations are more dense close to continental shelves and canyons, probably because of easier feeding. Sperm Whales are usually found in deep off-shore waters, but may be seen closer to shore in areas where the continental shelf is small.
Population and hunting
The total number of Sperm Whales throughout the world is unknown. Crude estimates, obtained by surveying small areas and extrapolating the result to all the world's oceans, range from 200,000 to 2,000,000 individuals. Although the Sperm Whale was hunted for several centuries for its meat, oil and spermaceti, the conservational outlook for Sperm Whales is brighter than that for many other whales. Although a small-scale coastal fishery still occurs in Indonesia, they are protected practically worldwide. Fishermen do not catch the deep-sea creatures that Sperm Whales eat, and the deep sea is likely to be more resistant to pollution than surface layers.
However, the recovery from the whaling years is a slow process, particularly in the South Pacific, where the toll on males of a breeding age was severe.
Watching Sperm Whales
Sperm Whales are not the easiest of whales to watch, due to their long dive times and ability to travel long distances underwater. However, due to the distinctive look and large size of the whale, watching is increasingly popular. Sperm Whale watchers often use hydrophones to listen to the clicks of the whales and locate them before they surface. Popular locations for Sperm Whale watching include the picturesque Kaikoura on New Zealand's South Island, where the continental shelf is so narrow that whales can be observed from the shore, and Andenes and Tromsø in arctic Norway. Dominica is believed to be the only Caribbean island with a year-round residential pod of females and calves.
In the news
Female in Dominican Pod, 2005In July 2003 a huge blob of white flesh was found washed up on a beach on the coast of southern Chile. The 12-metre-long (40 ft) mass of gelatinous tissue gave rise to speculation that a previously unknown giant octopus had been discovered. However, researchers at the Museum of Natural History, Santiago concluded that the mass was in fact the innards of a Sperm Whale, a conclusion drawn by looking at the dermal glands. When a Sperm Whale dies, its internal organs rot, until the animal becomes little more than a semi-liquid mass trapped inside the skin. In this case, the skin will eventually burst, causing the internal mass to float free and eventually wash up on the beach .
Dead Sperm Whales float towards shore quite often. Apart from the disposal issues identified above, beach managers fear that sharks, in particular the Great White Shark, will be attracted towards the beach by the rotting flesh, and potentially cause danger to beach users. For this reason, dead Sperm Whales are often towed out to sea before they become properly beached. This occurred twice in May 2004, once off Oahu in Hawaii where a dead whale was towed out 35 miles to sea but floated back to shore two days later.
Perhaps the most famous piece of Sperm Whale lore dates from 1970, when a long-dead, 8 short ton (7.25 tonne), 45 foot (13.7 m) long specimen came to the beach south of Florence, Oregon. For a time, it was a curiosity to local residents. As the beach is public right-of-way, it was the duty of the Oregon State Highway Division to dispose of it. They filled the animal with a half-ton of dynamite. On Thursday, November 12, the dynamite was set off, but the blast did not go toward the Pacific as planned. No one was hurt, but a car was crushed by falling blubber. Onlookers were covered with noxious-smelling bits of dead whale .
January 2004 saw a more dramatic entry of the Sperm Whale into the global media spotlight. A dead specimen of the whale, 17 metres long and weighing 50 tonnes, had washed up on a local beach in Tainan City, Taiwan. On being transported to a university in the city, gas pressure from decomposition built up inside the body, causing an explosion. Nobody was hurt, but blood and entrails were spread over several cars and surrounding pedestrians.
|Taipan||Jan 11 2012, 09:30 PM Post #2|
Found some good information of Orca pod attacks on Sperm Whales, which includes the behaviour of both species.
Killer whale predation on sperm whales : Observations and implications
"In October 1997 we observed a herd of approximately 35 killer whales (Orcinus orca) attack a pod of nine sperm whales (Physeter macrocephalus) 130 km off the coast of central California. During the four hours we watched, adult female killer whales, including some with calves, attacked in waves of four to five animals in what was apparently a wound and withdraw strategy. Adult male killer whales stood by until the very end when one charged in and quickly killed a seriously wounded sperm whale that had been separated from the group. The sperm whales appeared largely helpless: their main defensive behavior was the formation of a rosette (marguerite-heads together, tails out). When the killer whales were successful in pulling an individual out of the rosette, one or two sperm whales exposed themselves to increased attack by leaving the rosette, flanking the isolated individual, and leading it back into the formation. Despite these efforts, one sperm whale was killed and eaten and the rest were seriously, perhaps mortally, wounded. We also present details of two other encounters between sperm whales and killer whales that we observed. Although sperm whales, because of various behavioral and morphological adaptations, were previously thought to be immune to predation, our observations clearly establish their vulnerability to killer whales. We suggest that killer whale predation has potentially been an important, and underrated, selective factor in the evolution of sperm whale ecology, influencing perhaps the development of their complex social behavior and at-sea distribution patterns."
|Taipan||Jan 11 2012, 09:31 PM Post #3|
Sperm Whale - Records
"They are probably the deepest air-breathing divers on the planet.
They have the biggest head for their size of any animal (up to one third of their body length).
Sperm whales apparantly have the biggest brain (9 kg or 20 pounds) of any animal that has every lived on this planet (what they are doing with all that brain, no one is sure).
They are almost certainly the largest toothed predator that has ever lived, and they have the biggest teeth (25cm or 10 inches long).
It is thought that sperm whales have the lowest reproductive rate of any animal - not necessarily a good trait.
Sperm whales carry in their great huge heads the world's largest natural sound producing organ (unfortunately for them this organ is full of a fat called spermaceti that was once very popular amongst humans for making a high grade oil).
During the height of whaling they were the most hunted of any whale and probably more sperm whales were killed than any other species of whale - a record they would probably rather not have had.
The difference in size between male and female sperm whales is the greatest of all the cetaceans. The females are only two-thirds the length, and one third the mass, of the big males. Another example of how body mass changes faster than length.
The tail-flukes (tail flippers or tail fin to we land-lubbers) are the largest with respect to the whale's size of any of the cetaceans. "
|Taipan||Jan 11 2012, 09:32 PM Post #4|
Ecologists Home In On How Sperm Whales Find Their Prey
Science Daily — Ecologists have at last got a view of sperm whales' behaviour during their long, deep dives, thanks to the use of recently developed electronic "dtags". According to new research published in the British Ecological Society's Journal of Animal Ecology, sperm whales – like bats – use echolocation consistently to track down their prey at depth.
Working in the Atlantic, the Gulf of Mexico and the Ligurian Sea, scientists from Woods Hole Oceanographic Institution and the University of St Andrews attached acoustic recording tags to the dorsal surface of sperm whales with suction cups. The whales were then tracked acoustically with a towed hydrophone array.
The researchers used the tags to record the sounds that sperm whales produce while foraging. As sperm whales descended from the surface, they emitted a regular series of "clicks". When the whales reach the bottom of their dive, these clicks are emitted more often, eventually merging together to form "buzzes" of sound. This pattern reflects the whales homing in on cephalopods such as squid, with the buzzes reflecting the animals' final approach when detailed information on the squid's position and movement are required, the researchers believe.
Dr Stephanie Watwood and colleagues found that sperm whales produced buzzes on every deep dive they made, in all three locations, suggesting that they are highly successful at locating prey in the dark ocean depths.
The sperm whale is the world's largest deep-diving toothed whale, feeding mainly on squid, but until now little has been known about the timing of prey detection and capture during dives.
"Due to the difficulty of observing sperm whales during their long, deep dives, little has been known about their subsurface behaviour, giving rise to an array of speculations on how sperm whales find prey, including luring, touch, passive listening, echolocation and vision. Recording vocalisations of diving sperm whales presents a non-invasive opportunity to document feeding activity." says Watwood.
Note: This story has been adapted from a news release issued by Blackwell Publishing Ltd..
|Taipan||Jan 11 2012, 09:32 PM Post #5|
Male-Male Fights May Have Taught 'Moby Dick' and Real Whales to Sink Ships
August 26, 2002 -- Male sperm whales that rammed and sank ships - the inspiration for the fictional "Moby Dick" - may have evolved such aggressive behavior when they butted heads in fights over females, according to a study by University of Utah biologists.
"Herman Melville's 'Moby Dick' was based on the sinking of a real ship, the Essex, by a big sperm whale in 1820," says David Carrier, an associate professor of biology. "We believe this ability to sink ships is the result of whales evolving so that males could butt heads to compete for females."
Biology student Jason Otterstrom, who co-authored the study for his undergraduate research project, says: "We were trying to find out how sperm whales are able to hit ships so much bigger than them and swim away. Humans can't run into things that much bigger than us, and come away unfazed. … We make a fairly strong argument that the body of a sperm whale is designed to withstand severe impacts unharmed. It is evolutionarily advantageous to their survival."
The study was published in The Journal of Experimental Biology on June 15. Carrier and Otterstrom conducted it with postdoctoral fellow Stephen Deban.
Carrier says that while there have been other accounts of sperm whales sinking ships, only two are well-documented: the 1820 Essex incident, and the 1851 sinking of the Ann Alexander, also in the Pacific. The Ann Alexander's crew was rescued.
Carrier was inspired to conduct the study after reading Nathaniel Philbrick's 2000 book, "In the Heart of the Sea: The Tragedy of the Whaleship Essex," about how an 85-foot-long, 80-ton sperm whale rammed the Essex in the Pacific Ocean in 1820, punching a hole in the ship and sinking it in 10 minutes. The 20 crew members survived the sinking and fled in three rowboats, but 12 of them died of starvation or dehydration as they attempted to reach South America.
"What caught my attention was the audacity that whale had to attack a ship three or four times it's size and built out of solid oak," Carrier says. "The whale thought he could take on the ship. And he was right."
Melville learned details of the Essex in 1840 when he worked aboard a whaling ship and met the son of Owen Chase, who was first mate of the Essex and who wrote an 1821 book about the incident. Carrier says Chase's book argued the forehead of sperm whales is a battering ram.
The sinking of the Essex inspired Melville's 1851 novel "Moby Dick," which tells the story of Ahab, an old whaler who had lost a leg to Moby Dick in an earlier encounter and sets out on the ship Pequod to seek vengeance. After the giant whale escapes during two bouts, Ahab declares: "Forehead to forehead I meet thee, this third time, Moby Dick!" - a line Carrier quotes at the beginning of his study.
A major part of the whale study involved studying the relationship between the sexual dimorphism - the male-female size difference - of various species of cetaceans (whales, dolphins and porpoises) and the size of each species' forehead or "melon."
In polygynous species - those in which individual males reproduce with a harem of many females - males compete for access to the females. And the bigger the male-female size difference, the larger the harem, the more intense the competition among males and the larger the weapon used if the competition results in fighting. That is because the biggest males with the biggest weapons successfully reproduce and pass on their genes.
"Among groups of mammals, you find the species with the largest harems also have the largest weapons," Carrier says. Among antelope, for example, "the larger the harem, the larger the size of the antlers."
Carrier and colleagues examined data on 21 species of cetaceans and found "those species in which males are much larger than females tend to have the largest foreheads. If the forehead was the battering ram used for male-male aggression, then you would expect it would be relatively larger in those species in which males are larger than females" and compete more vigorously for females.
"The findings are consistent with the weapon hypothesis" and head-butting among male sperm whales, Carrier says.
In the second part of the study, Carrier and colleagues used computers to simulate head-butting collisions between average-size sperm whales weighing about 86,000 pounds (39,000 kilograms), with the attacker swimming at almost 7 mph.
A sperm whale's forehead "is a third of the length of the whale from front to back," Carrier says. "It's a big forehead, and is anywhere from 25 to 30 percent of the weight of the whale."
It includes the spermaceti sac, which is the upper chamber of the forehead filled with the oil prized by whalers, and the "junk," which is a lower chamber that contains thicker oil and is divided by vertical sheets of connective tissue.
"For our hypothesis to work, the forehead has to function both as a battering ram and as a shock absorber to protect the attacking whale," says Carrier. "We envision the forehead acting basically like an airbag in your car. We used a wide variety of shock-absorption values in the head-butting simulation because we don't know the true values."
He says the computer simulations aimed to determine "is there enough energy in the momentum of that forehead to damage another whale of equal size? We found there was. Also, when you give the attacking whale enough shock absorption to protect itself, the energy delivered to the target whale still appears to be large enough to do serious injury."
The Utah researchers' study has generated skepticism among some marine mammal experts. They contend sperm whales use their forehead or melon to aim sounds so they can communicate with other whales and use sound waves to locate objects in their environment.
"There is no doubt it is involved in focusing sound for sonar and communication," Carrier says. "But we are suggesting it also may be involved in male-male aggression and used as battering ram."
Critics, however, wonder why whales would risk damage to a sound-focusing organ by using it as a battering ram. Carrier says photos of sperm whales show tooth-mark scars on the junk, indicating the lower part of the forehead is used as the impact surface, while the overlying spermaceti - the main area where sounds are focused - adds to the momentum of impact.
Carrier acknowledges that a weakness of the study is that he lacked the time and money to directly measure the forehead sizes of the 21 species of whales, dolphins and porpoises. Instead, the sizes used in the study were based on those shown in a well-known field guide. But he says any errors in forehead sizes in those drawings are unlikely to affect the conclusion that cetacean species with larger foreheads also had a larger male-female size difference.
Carrier says he and his colleagues are not whale experts, but "I have a lot of confidence in the hypothesis. All the bits and pieces fit together," including sperm whales sinking ships, scars on their foreheads and the prevalence of head butting among related species.
Male hippopotamuses - which may be the closest living relative of whales and other cetaceans - engage in "open-mouthed charges where they ram their open mouths together and get in a pushing contest," he says.
Carrier says some other whale species have been observed butting heads, so "it shouldn't come as a surprise that sperm whales may also."
|Taipan||Jan 11 2012, 09:33 PM Post #6|
Bill Gilly, professor of biological sciences at Stanford’s Hopkins Marine Station, holds a jumbo squid captured in the Gulf of California off Mexico’s Baja peninsula in 2003. One of the largest cephalopods in the Pacific, the jumbo squid dives to depths of 1,300 feet in pursuit of lantern fish and other prey.
|Taipan||Jan 11 2012, 09:33 PM Post #7|
Sperm Whales Spotted Attacking Megamouth Shark
Department of Zoology, University of Milano, Milano, Italy.
Manado, North Sulawesi, Indonesia, 30th August '98, 10:00 am - we were studying the whale population with a group of WWF Italy volunteers off the coast of the island of Nain in the Bunaken archipelago (124° 50' 3" N, 1° 46' W) when we witnessed a remarkable event. While looking for cetaceans we encountered three examples of Sperm whales (Physeter macrocephalus) "attacking" a shark. As our boat approached, the 10-12 meters long, the Sperm whales swam off.
At this point we clearly saw the profile of a large shark (about 5 meters). The base of the dorsal fin and the gills showed signs of the whales' attack and the shark was swimming slowly and still rather bewildered at the surface. It was probably a planktivorous shark with a large head in proportion to its body. It had white marks on the tips of its fins and mouth and a dark triangular mark under its throat. The upper lobe of the caudal fin was very large. We had found an extremely rare specimen of Megamouth shark (Megachasma pelagios)!
Megamouth sharks are plankton-feeder deep sea animals. It is very rare to meet and observe them near the surface where they usually come only at night, following small crustacean preys. Sperm whales are usually considered squid feeders but there are a few notes about small deep sea sharks' presence in their diet.
Since the last sighting of Megachasma pelagios (the eleventh) in Cagayan de Oro (Philippines) on 21st February 1998, this is one of the few sightings in open sea as opposed to animals that were stranded or caught in fishing nets. It is also a significant event for studies of the relationship between whales and sharks - was it an attack, playfulness or just curiosity that attracted the Sperm whales to the Megamouth shark?
|Taipan||Jan 11 2012, 09:34 PM Post #8|
Thieving Whale Caught On Video Gives Rare Clues About Hunting Strategy, Sound Production
ScienceDaily (May 21, 2009) — For decades scientists have been intrigued by the variety of sounds emitted by sperm whales, partly due to a popular theory that suggests that the sounds might contain information about the animals' size. But historically it has been extremely difficult to demonstrate that these curious clicking noises can reveal information about the physical characteristics of the massive marine mammals. Now, researchers at Scripps Institution of Oceanography at UC San Diego are unlocking some of the mysteries of sperm whale sound production.
In a paper published in the May issue of the Journal of the Acoustical Society of America, Delphine Mathias and Aaron Thode of Scripps Oceanography for the first time describe a direct comparison between sperm whale clicking sounds and the physical features of the animal's head, including its size and internal organ structure.
The study provides a glimpse into a possible new approach for investigating the biology behind marine mammal sounds and perhaps more accurately counting their populations.
The roots of the unique study began years ago in Alaska, after sperm whales developed the ability to steal black cod off "longlines," deep-sea fishing gear that features a main fishing line draped across the ocean and fastened with shorter lines bearing baited hooks. Frustrated black cod fishermen began to realize that their longline fishing boats were attracting groups of whales—which typically forage alone— to their longlines, somehow alerting the animals like a dinner bell.
To help fishermen and scientists better understand this behavior, Scripps researchers deployed acoustic recorders on longlines in 2004 off Sitka, Alaska, as part of the Southeast Alaska Sperm Whale Avoidance Project (SEASWAP). The results helped identify the sounds that attract whales to the fishing vessels. Encouraged, the researchers added video cameras to the fishing gear in 2006, which led to some unexpected results.
The resulting video, recorded using ambient light at 100 meters (328 feet) depth, not only successfully gave the fishermen a clear idea of how the thieving whales were stealing the fish—they pluck the line at one end to jar the black cod free at the other end, somewhat like shaking apples from a tree—but it gave scientists a chance to match the animal's acoustics with video depictions of its physical features. Sperm whales typically dive to dark depths spanning 300 to 2,000 meters (984 to 6,500 feet) to catch prey, making it virtually impossible to capture such activity on video. The fact that the animals produce foraging sounds at such shallow depths around fishing vessels is the main reason the Alaska footage is so unique.
The clicks emitted by the whales are produced more rapidly as they approach their targets of interest and are among the loudest and most intense sounds produced by any animal, according to Thode, an associate research scientist with Scripps Oceanography's Marine Physical Laboratory.
"The sounds can be louder than a firecracker," said Thode. "But until this video recording was made, scientists had not been able to get a direct measurement of the size of the animal and the foraging sounds at the same time."
The Alaska video allowed Mathias and Thode to not only match the size of the whale's head with its acoustic signal, but permitted them to infer the size of its spermaceti organ, which produces a white, waxy substance previously used in candles and ointments, as well as the so-called "junk" inside the whale's head. The junk is a large organ that is believed to play a role in transmitting sound from the whale's head.
Thode said the study could be a first step in the broader use of acoustics to census whale populations as supplements to visual counts of the animals. Currently it is difficult to relate the number of whale sounds recorded to the number of animals present. The ability to tease individuals apart acoustically would be a basic step toward solving the problem.
"It's interesting to see if you can identify an individual animal from its sounds and that's something people have been fascinated by for a long time," said Thode. "Humans can recognize individual people over the telephone using features of their sounds, but it's been quantitatively very difficult to do this for individual animals."
Thode said the video also may assist fishermen in reducing sperm whale encounters with their gear. Besides being economically damaging, the encounters are potentially dangerous to both humans and marine mammals due to the possibility of entanglement. Thode said the video recording has encouraged the U.S. National Marine Fisheries Service to start deploying acoustic recorders during black cod surveys off the Alaskan Coast to measure the scale of the sperm whale problem.
The research was supported by the National Geographic Society and North Pacific Research Board.
Snapshots from the unique May 31, 2006, sperm whale video off Sitka, Alaska.
|Taipan||Jan 11 2012, 09:37 PM Post #9|
Giant Squid Eaten by Sperm Whale
October 29, 2009—Carrying the remains of a roughly 30-foot (9-meter) giant squid in her jaws, a female sperm whale, with a calf at her side, swims near the surface off Japan's Bonin Islands (map)in the northwestern Pacific. Taken on October 15, this and other "absolutely sensational" new pictures offer rare proof of the sperm whale's taste for giant squid, said giant squid expert Steve O'Shea of the Auckland University of Technology in New Zealand.
The pictures may also reveal that adult sperm whales, which grow up to 59 feet (18 meters) long, use pieces of their prizes to teach youngsters how to catch their own, O'Shea told National Geographic News.
The group of five adults and one calf kept diving deep in unison, which the apparent mother carrying the squid, photographer Tony Wu told the Daily Mail. "It seemed as if the adult whales were trying to teach the baby to dive and also to eat squid," he said.
Eating on the run, a female sperm whale carries the remains of a giant squid off the Bonin Islands, about 621 miles (1,000 kilometers) south of Tokyo, on October 15, 2009.
The whale almost certainly carried the giant morsel up from the dark depths of the nearby Osagawara Trench, a favorite hunting ground of sperm whales. The whales routinely dive for an hour or more to depths of up to 3,280 feet (1,000 meters) in pursuit of giant squid, which are thought to rarely venture higher than 1,000 feet (300 meters) below sea level.
Battles between giant squid and sperm whales often leave the whales scarred with sucker marks. Until recently, such wounds--along with analysis of sperm whale stomach contents--were the only proof of the whales' appetite for giant squid.
female sperm whale, carrying a piece of giant squid in her mouth, leads a gargantuan dinner party in the northwestern Pacific on October 15, 2009. Sperm whales are voracious hunters of squid, and one animal can consume an estimated 110 million tons a year.
Aiding the sperm whale in its hunts is the world's largest brain, which is surrounded by patches of spermaceti. Once used in candles and ointments, the white, waxy substance was long ago mistaken for the whale's sperm, leading to the species' curious name.
Part of a sperm whale's catch--a giant squid--drifts free in one of the rare pictures captured in the Pacific on October 15, 2009.
The whale at right was also photographed carrying the giant morsel in her mouth--rare evidence of the whales' taste for giant squid, which some researchers say can grow to 43 feet (13 meters) long and weigh more than 600 pounds (272 kilograms).
The whales use sophisticated echolocation--similar to sonar--to find their quarry in the pitch blackness of the deep.
An 11.5-foot-long (3.5-meter-long) leftover, this giant squid arm was recovered from the scene of the sperm whale feeding frenzy photographed off Japan on October 15, 2009.
At the same site in 2006, a Japanese expedition captured the first ever images of a live giant squid.
|Taipan||Jan 11 2012, 09:37 PM Post #10|
Sperm whale groups 'may corral deep squid'
By Victoria Gill
Science reporter, BBC News, Portland
Page last updated at 11:07 GMT, Tuesday, 23 February 2010
Sperm whales may team up and hunt collaboratively, scientists have suggested.
A US research team used hi-tech tags to glimpse some of the giant marine mammals' remarkable hunting behaviour.
This tracking showed how the whales travelled together in groups, but when they hunted, each whale "varied its role" within the group.
The research team announced the findings at the Ocean Sciences meeting in Portland, Oregon.
Professor Bruce Mate from the Hatfield Marine Science Center in Oregon led the study.
"The unique thing about this study is this new piece of equipment," he explained.
"We have [a tag with] GPS precision for the whales' movements and a time and depth record of their dives.
"And, for the first time, we have tagged several animals within the same group."
Professor Mate showed tracking evidence of the whales sticking closely together over several months - swimming around the Gulf of Mexico.
But as the huge mammals made their dives - hunting squid at depths reaching more than 1,000m - their behaviour varied with each dive.
"We can see that they're actually changing their role over time," he said.
"And we're speculating that the animals are herding a ball of squid."
He said that some whales appeared to guard the bottom of this "bait ball", preventing the prey from sinking to unreachable depths, while other animals in the group took advantage of the centre of the ball.
"It may be that each individual takes it in turns to do the most physiologically demanding task - the deep dive," he said.
Professor Hal Whitehead, a researcher from Dalhousie University in Nova Scotia, Canada, who studies whales, was impressed by the data, but said the suggestion that whales might be herding a ball of squid may be a little "far-fetched".
However, Dr Mate pointed out that previous research had shown this type of herding behaviour in dolphins.
In that case, scientists were able to capture footage of the dolphins herding a ball of fish, and appearing to take turns to dive through the ball for a mouthful.
Dr Mate explained that, with sperm whales, which dive to great depths, it was far more difficult to capture the behaviour.
"Our next step will be to image the squid at the same time as tracking the whales," he said. "And to tag more members of the same group so that we can track their movements."
|Taipan||Jan 11 2012, 09:38 PM Post #11|
Oil Spill to Wipe Out Gulf's Sperm Whales?
Just three dead whales could push the Gulf population over the edge, experts say.
A beached sperm whale lies in the surf near Port Aransas, Texas, on the U.S. Gulf Coast in 2008.
Photograph by Rachel Denny Clow, Corpus Christi Caller-Times/AP
for National Geographic News
Published May 21, 2010
If the Gulf of Mexico oil spill kills just three sperm whales, it could seriously endanger the long-term survival of the Gulf's native whale population, scientists say.
Right now between 1,400 and 1,660 sperm whales live year-round in the Gulf of Mexico, making up a distinct population from other Atlantic Ocean groups, in which males make yearly migrations.
All sperm whales are considered endangered under the U.S. Endangered Species Act. But the Gulf of Mexico population is thought to be especially vulnerable due to its relatively small size.
The whales are now at risk from the ongoing Deepwater Horizon oil spill, because they are likely to ingest or inhale toxic crude and noxious oil fumes. (See pictures of the oil seeping into Louisiana marshes.)
"We know there's going to be some [oil] exposure, and we know there's an endangered species. If you put those two thing together, there is reason for concern," said Celine Godard-Codding, an environmental toxicologist at Texas Tech University.
A 2009 stock assessment report by the National Oceanic and Atmospheric Administration (NOAA) estimated that the potential biological removal, or PBR, level for the Gulf of Mexico sperm whale population is three.
That means the whales' long-term survival is at risk if, in addition to natural deaths, three sperm whales a year are killed or removed by human causes.
The loss of a handful of whales each year can impact a population of hundreds, because sperm whales—especially females—require a very long time to reach sexual maturity. Females then give birth to just three or four calves during their entire lifetimes.
"They're like humans. Most of the human population is not going to have six kids at once and do that every year," Godard-Codding said.
"As soon as we get to the level of three deaths caused by human interaction—and this would include the oil spill—that would jeopardize that particular sperm whale population."
Whales May Be Choked, Drowned, and Poisoned
Oil spills can affect sperm whales and other cetaceans, including dolphins, in a number of ways.
For starters, the marine mammals have to surface to breathe, and if they come up through an oil slick, they can suck the toxic substance into their lungs.
Also, the fumes on the surface of the water after a recent spill can be powerful enough to knock out full-grown whales, causing them to drown. (Read an eyewitness account of smelling the Gulf oil spill.)
Finally, the oil can taint the toothed whales' prey—fish and squid—affecting the whales' diets and hurting their chances of raising healthy calves. (See pictures of a sperm whale eating a giant squid.)
"The chemicals in the oil product that move up through the food web are a great concern for us," said Teri Rowles, coordinator of NOAA's marine-mammal health and stranding response program.
Previous studies have shown that at least some of the Gulf of Mexico sperm whales are known to hang around where the Deepwater Horizon oil rig was located before it exploded on April 20, triggering the spill.
"Between 2000 and 2005, about 300 [sperm] whales were seen on a consistent basis right in that area," Texas Tech's Godard-Codding said.
Dead Gulf Sperm Whales Hard to Tally
Some experts worry that the Gulf oil spill could be as damaging to sperm whales as the 1989 Exxon Valdez oil spill was to killer whales in Alaska's Prince William Sound. (See pictures of oil lingering in Alaska 20 years after Exxon Valdez.)
After the Exxon Valdez disaster, some populations of killer whales were reduced by as much as 40 percent, according to a 2008 study led by marine biologist Craig Matkin of the North Gulf Oceanic Society in Alaska.
Even now, that killer whale population has yet to recover and will likely go extinct in a few decades, Matkin said.
"We lost so many females out of that group that they couldn't catch up again. They still haven't caught up," he said.
If the current oil spill causes more than three Gulf sperm whale deaths this year, it could push that group into the "red zone," Matkin said.
Whether marine mammals are being affected by the Gulf oil spill is unclear. Oil is a suspected factor in the stranding of several coastal bottlenose dolphins (picture), but a firm link has yet to be established, NOAA's Rowles said.
"Deep-diving whales, like sperm whales living away from the shore"—and thus closer to the main body of the oil slick—"certainly have been exposed," she added.
Finding dead or affected whales will be difficult, however, because the animals spend most of their time underwater, and their bodies do not often wash ashore.
"In the aerial surveys that are being performed as part of the cleanup and marine-mammal observations, we are requesting that people report dead floating whales," Rowles said.
"That would be the most likely way we would detect dead sperm whales."
|Taipan||Jan 11 2012, 09:39 PM Post #12|
Sperm whale faeces 'offset CO2 emissions'
Page last updated at 21:33 GMT, Tuesday, 15 June 2010 22:33 UK
By Richard Black
Environment correspondent, BBC News
Sperm whales may put a gentle (and unwitting) brake on climate change
Sperm whale faeces may help oceans absorb carbon dioxide from the air, scientists say.
Australian researchers calculate that Southern Ocean sperm whales release about 50 tonnes of iron every year.
This stimulates the growth of tiny marine plants - phytoplankton - which absorb CO2 during photosynthesis.
The process results in the absorption of about 40,000 tonnes of carbon - more than twice as much as the whales release by breathing, the study says.
The researchers note in the Royal Society journal Proceedings B that the process also provides more food for the whales, estimated to number about 12,000.
Phytoplankton are the basis of the marine food web in this part of the world, and the growth of these tiny plants is limited by the amount of nutrients available, including iron.
Over the last decade or so, many groups of scientists have experimented with putting iron into the oceans deliberately as a "fix" for climate change.
Not all of these experiments have proved successful; the biggest, the German Lohafex expedition, put six tonnes of iron into the Southern Ocean in 2008, but saw no sustained increase in carbon uptake.
The Lohafex expedition was the latest to probe iron fertilisation
Although 40,000 tonnes of carbon is less than one-thousandth of the annual emissions from burning fossil fuels, the researchers note that the global total could be more substantial.
There are estimated to be several hundred thousand sperm whales in the oceans, though they are notoriously difficult to count; and lack of iron limits phytoplankton growth in many regions besides the Southern Ocean.
So it could be that whale faeces are fertilising plants in several parts of the world.
Crucial to the idea is that sperm whales are not eating and defecating in the same place - if they were, they could just be absorbing and releasing the same amounts of iron.
Instead, they eat their diet - mainly squid - in the deep ocean, and defecate in the upper waters where phytoplankton can grow, having access to sunlight.
Releasing the iron here is ultimately good for the whales as well, say the researchers - led by Trish Lavery from Flinders University in Adelaide.
Phytoplankton are eaten by tiny marine animals - zooplankton - which in turn are consumed by larger creatures that the whales might then eat.
The scientists suggest a similar mechanism could underpin the "krill paradox" - the finding that the abundance of krill in Antarctic waters apparently diminished during the era when baleen whales that eat krill were being hunted to the tune of tens of thousands per year.
|Taipan||Jan 11 2012, 09:39 PM Post #13|
Whales Have Accents and Regional Dialects: Biologists Interpret the Language of Sperm Whales
ScienceDaily (May 12, 2011) — Dalhousie Ph.D. student Shane Gero has recently returned from a seven-week visit to Dominica. He has been traveling to the Caribbean island since 2005 to study families of sperm whales, usually spending two to four months of each year working on the Dominica Sperm Whale Project. One of the goals of this project is to record and compare whale calls over time, examining the various phrases and dialects of sperm whale communities.
When they dive together, sperm whales make patterns of clicks to each other known as "codas." Recent findings suggest that not only do different codas mean different things, but that whales can also tell which member of their community is speaking based on the sound properties of the codas. Just as we can tell our friends apart by the sounds of their voices and the way they pronounce their words, different sperm whales make the same pattern of clicks, but with different accents.
Caribbean and Pacific whales have different repertoires of codas, like a regional dialect, but the "Five Regular" call -- a pattern of five evenly spaced clicks -- is thought to have the universal function of individual identity because it is used by sperm whales worldwide.
These discoveries were recently published in the journal Animal Behaviour, in an article authored by University of St. Andrews PhD student Ricardo Antunes, Dal alumnus Tyler Schulz, Mr. Gero, Dal professor Dr. Hal Whitehead, and St. Andrews faculty members Dr. Jonathan Gordon and Dr. Luke Rendell.
Mr. Gero and Dr. Whitehead explain that the sperm whale's biggest threat is human pollution. Not only do humans introduce toxins into the ocean, but they also generate harmful sound pollution. Increased shipping traffic, underwater explosions caused by searching for oil, and military sonar all contribute to ocean noise that masks communication between whales. "No one wants to live in a rock concert," says Mr. Gero, adding that noise pollution is especially troublesome in the ocean because "it is a totally different sensory world." The sperm whales can dive to depths of over 1000 metres and depend on sound for communication and navigation in the pitch black of the deep water.
The Dominica Sperm Whale Project hopes to understand more about sperm whale society because, as Mr. Gero says, "it is infuriating that we know more about the moon than the oceans." He hopes to communicate a better understanding of life in the oceans to people by using these beautiful whales as examples, and by placing an emphasis on "how similar their lives actually are to ours."
The whales live in matriarchal social units composed of mothers, daughters, and grandmothers. Once males reach adolescence, they are ostracized from the group and travel towards the poles until they are ready to breed. Consequently, little is known about the males, but the roles of females in relation to their young have been studied extensively by Mr. Gero and Dr. Whitehead. Female whales will baby-sit each other's offspring while mothers are diving, forming a strong community that revolves around the upbringing of calves. "They are nomadic," explains Dr. Whitehead, "so the most important things in their lives are each other."
Dr. Whitehead enjoys researching sperm whales because of their "fascinating and complex social lives." He hopes the Dominica Sperm Whale Project will be able to trace how whale communities change through time.
Part of Mr. Gero's PhD includes studying how calves acquire their dialect. Baby sperm whales babble at first, and Mr. Gero is interested in discovering how the babies' diversity of calls gets narrowed down to the family repertoire.
"One of the most exciting parts [of returning to Dominica] is to go down and see who's around," says Mr. Gero, admitting that he has "become attached to the individual whales." For the first time, sperm whales can be studied as individuals within families, with such lovable nicknames as "Pinchy" and "Fingers." The family that includes these two whales is recognized as "the best studied social unit of sperm whales in the world."
Mr. Gero would like to continue working with the same groups of whales because a long-term project will offer a better understanding of their social developments. He "feels a responsibility to speak on [the whales'] behalf" and hopes to move toward conservation, while still remaining in the field of biology.
More information about the Dominica Sperm Whale Project can be found at: http://whitelab.biology.dal.ca/dswp/
Fingers and her baby Thumb swim together off the coast of Dominica.
Ricardo Antunes, Tyler Schulz, Shane Gero, Hal Whitehead, Jonathan Gordon, Luke Rendell. Individually distinctive acoustic features in sperm whale codas. Animal Behaviour, 2011; DOI: [url]10.1016/j.anbehav.2010.12.019[/url]
|Taipan||Jan 11 2012, 09:40 PM Post #14|
|DinosaurMichael||Jan 19 2012, 11:18 AM Post #15|
||This is my favourite Whale.|
Other sites I'm a member on.|
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