Sperm Whale

Appearance

The sperm whale's unique body is unlikely to be confused with any other species. The sperm whale's distinctive shape comes from its very large, block-shaped head, which can be one-quarter to one-third of the animal's length. The S-shaped blowhole is located very close to the front of the head and shifted to the whale's left. This gives rise to a distinctive bushy, forward-angled spray.


The sperm whale's flukes are triangular and very thick. The whale lifts its flukes high out of the water as it begins a feeding dive. It has a series of ridges on the back's caudal third instead of a dorsal fin. The largest ridge was called the 'hump' by whalers, and can be mistaken for a dorsal fin because of its shape and size.

In contrast to the smooth skin of most large whales, its back skin is usually wrinkly and has been likened to a prune by whale-watching enthusiasts. Skin is normally a uniform grey in color, though it may appear brown in sunlight. Albinos have also been reported.

Naming

The name ''sperm whale'' is an apocopation of ''spermaceti whale''. Spermaceti, originally mistaken for the whales' "sperm", is the semi-liquid, waxy substance found in the ''spermaceti organ'' or case in front of and above the skull bone and also in the ''junk'', the area below the spermaceti organ and just above the upper jaw. The case consists of a soft white, waxy substance saturated with spermaceti oil. The junk is composed of cavities filled with the same wax and spermaceti oil and intervening connective tissue.
The sperm whale is also known as the "cachalot", which is thought to derive from the archaic French for "tooth" or "big teeth", as preserved for example in ''cachau'' in the Gascon dialect . The etymological dictionary of Corominas says the origin is uncertain, but it suggests that it comes from the vulgar Latin ''cappula'', plural of ''cappulum'', sword hilt. According to Encarta Dictionary, the word ''cachalot'' came to English "via French from Spanish or Portuguese ''cachalote'', perhaps from [Portuguese] ''cachola'', 'big head'". The term is retained in the Russian word for the animal, кашалот , as well as in many other languages.The sperm whale belongs to the order Cetacea, the order containing all whales and dolphins. It is a member of the suborder Odontoceti, the suborder containing all the toothed whales and dolphins. It is the sole extant species of its genus, ''Physeter'', in the family Physeteridae. Two species of the related extant genus ''Kogia'', the pygmy sperm whale ''Kogia breviceps'' and the dwarf sperm whale ''K. simus'', are either placed in this family, or in the family Kogiidae. In some taxonomic schemes the families Kogiidae and Physeteridae are combined as the superfamily Physeteroidea .

The sperm whale is one of the species originally described by Linnaeus in 1758 in his 18th century work, ''Systema Naturae''. He recognised four species in the genus ''Physeter''. Experts soon realised that just one such species exists, although there has been debate about whether this should be named ''P. catodon'' or ''P. macrocephalus'', two of the names used by Linnaeus. Both names are still used, although most recent authors now accept ''macrocephalus'' as the valid name, limiting ''catodons status to a lesser synonym.

Distribution

The sperm whale is among the most cosmopolitan species. It prefers ice-free waters over 1,000 metres deep. Although both sexes range through temperate and tropical oceans and seas, only adult males populate higher latitudes.

It is relatively abundant from the poles to the equator and is found in all the oceans. It inhabits the Mediterranean Sea, but not the Black Sea, while its presence in the Red Sea is uncertain. The shallow entrances to both the Black Sea and the Red Sea may account for their absence. The Black Sea's lower layers are also anoxic and contain high concentrations of sulphur compounds such as hydrogen sulphide.

Populations are denser close to continental shelves and canyons. 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 and drops quickly to depths of 310–920 metres . Coastal areas with significant sperm whale populations include the Azores and the Caribbean island of Dominica.

Status

The number of sperm whales throughout the world is unknown, but is thought to be in the hundreds of thousands. The conservation outlook is brighter than for many other whales. Historically, Japan has taken ten sperm whales a year, and until 2006 tens of these whales were hunted off Indonesia. They are protected practically worldwide, and commercial whaling has ceased. Fishermen do not target the creatures that sperm whales eat. However, long-line fishing operations in the Gulf of Alaska have complained about sperm whales stealing fish from their lines.

Entanglement in fishing nets and collisions with ships represent the greatest threats to the sperm whale population currently. Other current threats include ingestion of marine debris, ocean noise, and chemical pollution. The IUCN regards the sperm whale as being "vulnerable". The species is listed as endangered on the United States Endangered Species Act.

The species is listed on Appendix I and Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals . It is listed on Appendix I as this species has been categorized as being in danger of extinction throughout all or a significant proportion of their range and CMS Parties strive towards strictly protecting these animals, conserving or restoring the places where they live, mitigating obstacles to migration and controlling other factors that might endanger them. It is listed on Appendix II as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. It is also covered by the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area and Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region
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Behavior

Females stay in groups of about a dozen individuals and their young. Mature males leave their "natal unit" somewhere between 4 and 21 years of age. Mature males sometimes form loose "bachelor groups" with other males of similar age and size. As males grow older, they typically live solitary lives. Mature males have beached themselves together, suggesting a degree of cooperation which is not yet fully understood.

The most common non-human attacker of sperm whales is the orca, but pilot whales and the false killer whale also sometimes harass them. Orcas prey on target groups of females with young, usually making an effort to extract and kill a calf. Female sperm whales repel these attacks by encircling their calves. The adults either face inwards to use their tail flukes against the orcas, or outwards, fighting with their teeth. This Marguerite formation, named after the flower, is also used by whales to support an injured unit member. Early whalers exploited this behavior, attracting a whole unit by injuring one of its members. If the orca pod is extremely large, its members may sometimes be able to kill adult female sperm whales. Large mature male sperm whales have no non-human predators, and are believed to be too large, powerful and aggressive to be threatened by orcas.

Reproduction

Sperm whales can live 70 years or more. They are a prime example of a species that has been K-selected, i.e., their reproductive strategy is associated with stable environmental conditions and comprises a low birth rate, significant parental aid to offspring, slow maturation, and high longevity.

How they choose mates has not been definitively determined. There is evidence that males have dominance hierarchies, and there is also evidence that female choice influences mating. Gestation requires 14 to 16 months, producing a single calf. Lactation proceeds for 19 to 42 months, but calves may suckle up to 13 years . Calves can suckle from females other than their mothers. Females generally have birth intervals of three to six years.

Females reach sexual maturity between 7 and 13 years; males follow beginning at 18 years. Upon reaching sexual maturity, males move to higher latitudes, where the water is colder and feeding is more productive. Females remain at lower latitudes. Males reach their full size at about age 50.

Food

Sperm Whales usually dive between 300 to 800 metres , and sometimes 1–2 kilometres to search for food. Such dives can last more than an hour. They feed on several species, notably the giant squid, the colossal squid, octopuses, and diverse fish like demersal rays, but the main part of their diet consists of medium-sized squid. Some prey may be taken incidentally while eating other items. Most of what is known about deep sea squid has been learned from specimens in captured sperm whale stomachs, although more recent studies analysed fecal matter. One study, carried out around the Galápagos, found that squid from the genera ''Histioteuthis'' , ''Ancistrocheirus'' , and ''Octopoteuthis'' weighing between 12 and 650 grams were the most commonly taken. Battles between sperm whales and colossal squid ) have never been observed by humans; however white scars are believed to be caused by the large squid. One study published in 2010 collected evidence that suggests that female sperm whales may collaborate when hunting Humboldt squid.

An older study, examining whales captured by the New Zealand whaling fleet in the Cook Strait region, found a 1.69:1 ratio of squid to fish by weight. Sperm whales sometimes steal Sablefish and Toothfish from long lines. Long-line fishing operations in the Gulf of Alaska complain that sperm whales take advantage of their fishing operations to eat desirable species straight off the line, sparing the whales the need to hunt. However, the amount of fish taken is very little compared to what the sperm whale needs per day. Video footage has been captured of a large male sperm whale "bouncing" a long line, to gain the fish....snipped... Sperm whales are believed to prey on the megamouth shark, a rare and large deep-sea species discovered in the 1970s. In one case, three sperm whales were observed attacking or playing with a megamouth.

The sharp beak of a consumed squid lodged in the whale's intestine may lead to the production of ambergris, analogous to the production of pearls. The irritation of the intestines caused by squid 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 100,000,000 short tons — a figure greater than the total consumption of marine animals by humans each year.

It is not well understood why the sperm whale's head is so large in comparison to the lower jaw. One theory is that the sperm whale's ability to echolocate through its head aids in hunting. However, squid, its main prey, may have acoustic properties too similar to seawater to reflect sounds. The sperm whale's head contains a structure called the phonic lips, also known as the monkey lips, through which it blows air. This can create clicks that have a source level exceeding 230 decibels re 1 micropascal referenced to a distance of 1 metre – in other words, it is by far the loudest sound made by any animal, and 10–14 dB louder than a powerful rifle sounds in air at 1 metre away. It has been hypothesised that clicks attempt to stun prey. Experimental studies attempting to duplicate this effect have been unable to replicate the supposed injuries, casting doubt on this idea.Spermaceti, obtained primarily from the spermaceti organ, and sperm oil, obtained primarily from the blubber in the body, were much sought after by 18th, 19th, and 20th century whalers. These substances found a variety of commercial applications, such as candles, soap, cosmetics, machine oil, other specialized lubricants, lamp oil, pencils, crayons, leather waterproofing, rust-proofing materials and many pharmaceutical compounds. Ambergris, a solid, waxy, flammable substance produced in the digestive system of sperm whales, was also sought as a fixative in perfumery.


Prior to the early 18th century, hunting was mostly by indigenous Indonesians. Legend has it that sometime in the early 18th century, around 1712, Captain Christopher Hussey, while cruising for right whales near shore, was blown offshore by a northerly wind, where he encountered a sperm whale pod and killed one. Although the story may not be true, sperm whales were indeed soon exploited by American whalers. Judge Paul Dudley, in his ''Essay upon the Natural History of Whales'' , states that one Atkins, ten or twelve years in the trade, was among the first to catch sperm whales sometime around 1720 off the New England coast.

There were only a few recorded catches during the first few decades of offshore sperm whaling. Instead sloops concentrated on Nantucket Shoals where they would have taken right whales or went to the Davis Strait region to catch bowhead whales. By the early 1740s, with the advent of spermaceti candles , American vessels began to focus on sperm whales. The diary of Benjamin Bangs shows that, along with the bumpkin sloop he sailed, he found three other sloops flensing sperm whales off the coast of North Carolina in late May 1743. On returning to Nantucket in the summer 1744 on a subsequent voyage he noted that "45 spermacetes are brought in here this day," another indication that American sperm whaling was in full swing.


American sperm whaling soon spread from the east coast of the American colonies to the Gulf Stream, the Grand Banks, West Africa , the Azores , and the South Atlantic . From 1770 to 1775 Massachusetts, New York, Connecticut, and Rhode Island ports produced 45,000 barrels of sperm oil annually, compared to 8,500 of whale oil. In the same decade the British began sperm whaling, employing American ships and personnel. By the following decade the French had entered the trade, also employing American expertise. Sperm whaling increased until the mid-19th century. Spermaceti oil was important in public lighting and for lubricating the machines of the Industrial Revolution. Sperm whaling declined in the second half of the 19th century, as petroleum came in to broader use. In that sense, it may be said to have protected whale populations from even greater exploitation. Sperm whaling in the 18th century began with small sloops carrying only one or two whaleboats. The fleet's scope and size increased over time, and larger ships entered the fishery. In the late 18th century and early 19th century sperm whaling ships sailed to the Pacific, the Indian Ocean, Japan, the coast of Arabia, Australia and New Zealand. Hunting could be dangerous to the crew, since sperm whales will readily fight to defend themselves against attack, unlike most baleen whales. When dealing with a threat, sperm whales will use their huge head effectively as a battering ram. Arguably the most famous sperm whale counterattack occurred on November 20, 1820, when a whale claimed to be about 25.9 metres long rammed and sank the Nantucket whaleship ''Essex''. Only 8 out of 21 sailors survived to be rescued by other ships. This instance is popularly believed to have inspired Herman Melville's famous "Moby Dick".


The sperm whale's ivory-like teeth were often sought by 18th and 19th-century whalers, who used them to produce inked carvings known as ''scrimshaw.'' Thirty teeth of the sperm whale can be used for ivory. Each of these teeth , are hollow for the first half of their length. Like walrus ivory, sperm whale ivory has two distinct layers. However, sperm whale ivory contains a much thicker inner layer. Though a widely practiced art in the 19th century, scrimshaw using genuine sperm whale ivory declined substantially after the retirement of the whaling fleets in the 1880s. Currently the Endangered Species Act and CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, prevents the sales of or trade in sperm whale ivory harvested after 1973 or in scrimshaw crafted from it.

Modern whaling was more efficient than open-boat whaling, employing steam-powered ships and exploding harpoons. Initially, modern whaling activity focused on large baleen whales, but as these populations were taken, sperm whaling increased. This was especially true during World War II when spermaceti, the fine waxy oil produced by sperm whales, was in high demand for lubricating the American war machine. In both the 1941-2 and 1942-3 seasons, the Norwegian expedition took over 3,000 sperm whales off the coast of Peru alone. After the war whaling continued unabated to obtain oil for cosmetics and high-performance machinery, such as automobile transmissions.

The hunting led to the near extinction of large whales including sperm whales until bans on whale oil use were instituted in 1972.International Whaling Commission gave the species full protection in 1985. Hunting by Japan in the northern Pacific Ocean continued until 1988.

It is estimated that the historic worldwide population numbered 1,100,000 before commercial sperm whaling began in the early 18th century. By 1880 it had declined by an estimated 29 per cent. From that date until 1946 the population appears to have recovered somewhat as whaling pressure lessened, but after the Second World War, the population declined even further, to only 33 per cent of the pre-whaling era. It has been estimated that in the 19th century between 184,000 and 236,000 sperm whales were killed by the various whaling nations, while in the modern era, at least 770,000 were taken, the majority between 1946 and 1980.

Sperm whales increase the levels of primary production and carbon export by depositing iron rich faeces into surface waters of the Southern Ocean. The iron rich faeces causes phytoplankton to grow and take up more carbon from the atmosphere. When the phytoplankton dies, it sinks to the deep ocean and takes the atmospheric carbon with it. By reducing the abundance of sperm whales in the Southern Ocean, whaling has resulted in an extra 2 million tonnes of carbon remaining in the atmosphere each year.

Remaining sperm whale populations are large enough that the species' conservation status is rated as vulnerable rather than endangered. However, the recovery from the whaling years is a slow process, particularly in the South Pacific, where the toll on breeding-age males was severe.

Evolution

Although the fossil record is poor, several extinct genera have been assigned to the clade Physeteroidea, which includes the last common ancestor of the modern sperm whale, pygmy sperm whale and dwarf sperm whale, plus
''all'' of that ancestor's descendants. These fossils include ''Ferecetotherium'', ''Idiorophus'', ''Diaphorocetus'', ''Aulophyseter'', ''Orycterocetus'', ''Scaldicetus'', ''Placoziphius'', ''Zygophyseter'' and ''Acrophyseter''. ''Ferecetotherium'', found in Azerbaijan and dated to the late Oligocene , is the most primitive fossil that has been found which possesses sperm whale-specific features such as an asymmetric rostrum . Most sperm whale fossils date from the Miocene period, million years ago. ''Diaphorocetus'', from Argentina, has been dated to the early Miocene. Fossil sperm whales from the Middle Miocene include ''Aulophyseter'', ''Idiorophus'' and ''Orycterocetus'', all of which were found on the west coast of the United States, and ''Scaldicetus'', found in Europe and Japan. ''Orycterocetus'' fossils have also been found in the North Atlantic Ocean and the Mediterranean Sea, in addition to the west coast of the United States. ''Placoziphius'', found in Europe, and ''Acrophyseter'', from Peru, are dated to the late Miocene.


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Evolutionary family tree of sperm whales,including simplified summary of extinct groups
Fossil sperm whales differ from modern sperm whales in tooth count and the shape of the face and jaws. For example ''Scaldicetus'' had a tapered rostrum. Genera from the Oligocene and early and middle Miocene, with the possible exception of ''Aulophyseter'', had teeth in their upper jaws. ''Acrophyseter'', from the late Miocene, also had teeth in both the upper and lower jaws as well as a short rostrum and an upward curving mandible . These anatomical differences suggest that fossil species may not have necessarily been deep-sea squid eaters like the modern sperm whale, but that some genera mainly ate fish. ''Zygophyseter'', dated from the middle to late Miocene and found in southern Italy, had teeth in both jaws and appears to have been adapted to feed on large prey, rather like the modern Orca .

Cultural

Rope-mounted teeth are important cultural objects throughout the Pacific. In New Zealand, the Māori know them as "rei puta" and were rare because sperm whales were not actively hunted in traditional Māori society. Whale ivory and bone were taken from beached whales. In Fiji the teeth are known as tabua and they were traditionally given as gifts for atonement or esteem , and were important in negotiations between rival chiefs. Friedrich Ratzel in ''The History of Mankind'' reported in 1896 that, in Fiji, whales' or cachalots' teeth were the most-demanded article of ornament or value. They occurred often in necklaces. Today the tabua remains an important item in Fijian life. The teeth were originally rare in Fiji and Tonga, which exported teeth, but with the Europeans' arrival, teeth flooded the market and this "currency" collapsed. The oversupply led in turn to the development of the European art of scrimshaw.

Herman Melville's novel ''Moby-Dick'' is based on a true story about a sperm whale that attacked the whaleship ''Essex''. Melville associated the sperm whale with the Bible's Leviathan. The fearsome reputation perpetuated by Melville was based on bull whales' ability to fiercely defend themselves from attacks by early whalers, occasionally resulting in the destruction of the whaling ships.

Jules Verne's ''Twenty Thousand Leagues Under the Sea'', mentions cachalots as preying on fellow whales.

The Sperm Whale was designated as the Connecticut state animal by the CT General Assembly in 1975. It was selected because of its specific contribution to the state's history and because of its present-day plight as an endangered species.