Thursday, August 23, 2007

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 waxy 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-Dick, have led many to describe it as the archetypal whale. Partly because of Melville, the Sperm Whale is commonly associated with the 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 the Azores. The Sperm Whale is also the state animal of Connecticut.


Main article: Spermaceti Spermaceti
Whales breathe air at the surface of the water through a single, s-shaped blowhole. The blowhole is located on the left side of the front of its huge head. They spout (breathe) 3–5 times per minute at rest, but the rate increases to 6–7 times per minute after a dive. The blow is a noisy, single stream that rises up to 15 m (50 ft) above the surface of the water and points forward and to the left of the whale at a 45° angle.

Spouting, and breathing

Ecology, behaviour and life history
Sperm Whales, along with bottlenose whales and elephant seals, are the deepest-diving mammals in the world.
They are believed to be able to dive up to 3 km (1.9 miles) in depth and 90 minutes in duration to the ocean floor. More typical dives are around 400 m (437 yards) in depth and 30–45 minutes' duration and generally moves in a northerly direction. According to Animal Planet's "The Most Extreme" (Episode:Natural Athletes), sperm whales are ranked the second as athletes. They can dive two miles deep with one gulp of air for two hours. They carry three tonnes of blood which holds enough oxygen to help it achieve its diving depth. That is twenty times deeper than any human can go, according to the show.
They feed on several species, in particular giant squid, octopuses and diverse fish like demersal rays, but the main part of their diet consists of medium sized squid. 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, given alone the fact that even some of the largest giant squid weigh only about 300 kg (660 lb), in contrast to several tons of even the youngest hunting sperm whale. Recently, an immature 495kg Giant Squid was caught by New Zealand fishermen in the Ross Sea. However, white scars on the bodies of Sperm Whales are believed to be caused by squid. The giant squid are considered to be the sperm whales prime diet, as large deep sea fish stocks are becoming depleted by humans. Stealing of Sablefish and Toothfish from long lines has been documented and well known also. It is believed that this trait is learned and passed on to other whales within the pod or offspring.
It is 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. The irritation of the intestines caused by the beaks stimulates the secretion of this lubricant-like substance. 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 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.

Sperm whale Feeding, behaviour and diving
The Sperm Whale is one of the many species originally described by Linnaeus in 1758 in his 18th century work, Systema Naturae; he recognised four species in the Physeter genus.

Taxonomy and naming

See also: Whaling
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.

Sperm whale Population and hunting
See also: Whale watching
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, Andenes and Tromsø in Arctic Norway and at the Azores where it can be seen throughout the year as opposed to other whales that are only seen during migration. Dominica is believed to be the only Caribbean island with a year-round residential pod of females and calves.

Watching Sperm Whales
In July 2003 a huge blob of white flesh was found washed up on a beach on the coast of southern Chile. The 12-metre (40 ft) long mass of gelatinous tissue

In the news

Main article: Exploding whales Exploding whales
In March 2007, a Japanese fisherman drowned after his boat was capsized by a panicked Sperm Whale he was trying to rescue. The whale had wandered into the relatively shallow waters in a bay in Shikoku.

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