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Sperm Whale
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The Sperm Whale (Physeter macrocephalus or Physeter catodon) is the largest of all toothed whales and largest living toothed animal. The whale was named after the milky-white waxy substance, spermaceti, found in its head and originally mistaken for sperm or semen. Historically the Sperm Whale has also been known as the common cachalot; "cachalot" is derived from an archaic French word for "tooth".
A bull Sperm Whale can grow up to long.
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Encyclopedia
The Sperm Whale (Physeter macrocephalus or Physeter catodon) is the largest of all toothed whales and largest living toothed animal. The whale was named after the milky-white waxy substance, spermaceti, found in its head and originally mistaken for sperm or semen. Historically the Sperm Whale has also been known as the common cachalot; "cachalot" is derived from an archaic French word for "tooth".
A bull Sperm Whale can grow up to long. It has a large head that can be up to one-third of the animal's length. It also has the largest brain of any animal in the world. It has a cosmopolitan distribution across the world's oceans. The species feeds on squid and fish, diving as deep as in order to obtain its prey, making it the deepest diving mammal in the world. Its diet includes Giant and Colossal Squid. It is considered the largest living predator and possibly the largest ever, not in terms of its taking animal matter (which is true of all cetaceans, including the larger baleen whales) but in that it actively preys on self-functioning animals. The Sperm Whale's clicking is the loudest sound produced by any animal, but there is still some uncertainty about its functions. These whales live in groups called pods. Pods of females and young live separately from older males. The females cooperate to protect and nurse their young. Females give birth to calves every three to six years, and care for the calves for more than a decade.
Over most of the period from the early 18th century until the late 20th century, the Sperm Whale was subjected to significant hunting pressure in order to obtain the spermaceti and other products, such as sperm oil and ambergris. Spermaceti found many important uses, such as candles, soap, cosmetics and machine oil. Due to its size, the Sperm Whale could sometimes defend itself effectively against whalers, a famous example being the Essex. As a result of whaling pressure, the Sperm Whale is currently listed as vulnerable by the IUCN. The Sperm Whale has few natural enemies, as few predators are strong enough to successfully attack a healthy Sperm Whale, however Orcas have been observed attacking pods and killing adult sperm whales. The Sperm Whale can live for more than 70 years.
Explanation of name
"Sperm whale" is an apocopation of Spermaceti Whale. Spermaceti is the semi-liquid, waxy substance found in the animal's head. The name derives from the late Latin sperma ceti (both words loaned from Greek) meaning "sperm of the whale" (strictly, "sperm of the sea monster"), as people mistook the substance for the whale's semen. Spermaceti is found in the spermaceti organ or case in front of and above the skull of the whale 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 be derived from an archaic French word for "tooth", for example cachau in the Gascon dialect.. The etymological dictionary of Corominas says the origin of the word is uncertain, but it suggests that it comes from the vulgar Latin cappula, plural of cappulum, hilt of a sword. According to Encarta Dictionary, the word cachalot came to English "via French from Spanish or Portuguese cachalote, perhaps from [Portuguese] cachola, 'big head'".
Description
Size
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The Sperm Whale is the largest toothed whale, with adult males measuring up to long and weighing up to . By contrast, the second largest toothed whale, Baird's Beaked Whale measures and weighs up to 15 tons. The Nantucket Whaling Museum has a jawbone of a sperm whale which is long. The jawbone is about 25% of the sperm whale's overall body length, which would mean the jaw bone came from a Sperm whale about long, although the Nantucket Whaling Museum claims this individual was in total; the whale that sank the Essex (whaleship) (one of the basis-forming incidents for Moby-Dick) was claimed to have a length of . Owing to extensive whaling, Sperm Whale size may have decreased, as males were heavily exploited during the modern era, primarily after World War II. Today, male sperm whales do not usually exceed in length or in weight.
It is among the most sexually dimorphic of all cetaceans, meaning males and females differ greatly. Mature males are typically 30% to 50% longer than mature females and three times as massive. However at birth both sexes are about the same size.
External appearance
The Sperm Whale's distinctive shape comes from its very large head, which is typically one-third of the animal's length. The 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 blow angled forward.
The Sperm Whale's flukes are also triangular and very thick. Flukes are lifted very high out of the water before a whale begins a deep dive. The Sperm Whale has no true dorsal fin. Instead, a series of ridges are present on the caudal third of the back. The largest ridge was called the 'hump' by whalers, and can be mistaken for a dorsal fin because of its shape.
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. It is normally a uniform grey in colour, though it may appear brown in sunlight. White albino whales have also been reported.
Jaws and teeth
The Sperm Whale has 20 to 26 teeth on each side of its lower jaw. The teeth are cone-shaped and weigh up to . The purpose of the teeth is unknown. Teeth do not appear to be necessary for capturing or eating squid, and well-fed Sperm Whales have been found in the wild without teeth. One hypothesis is that the teeth are used in aggression between males. Bull Sperm Whales often show scars which seem to be caused by the teeth of other bulls. Rudimentary teeth are also present in the upper jaw, but these rarely emerge into the mouth.
Respiration and diving
Sperm Whales, along with bottlenose whales and elephant seals, are the deepest-diving mammals in the world. Sperm whales are believed to be able to dive up to in depth and 90 minutes in duration to the ocean floor. More typical dives are around in depth and 35 minutes in duration. Because of the great depths to which they dive, Sperm Whales sometimes drown when entangled in transoceanic telephone cables.
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, reducing nitrogen intake, and the metabolism can decrease to preserve oxygen supplies. Myoglobin, which stores oxygen in muscle tissue, is much more abundant in Sperm Whales than terrestrial animals. These whales' blood has a high density of red blood cells, which contain hemoglobin which carries oxygen, and the oxygenated blood can be directed towards the brain and other essential organs only when oxygen levels deplete. The spermaceti organ may also play a role by adjusting buoyancy (see below).
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 to breathe for about eight minutes before diving again. Odontoceti (toothed 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 the head. Sperm whales 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. On average, females and immatures blow every 12.5 seconds before dives, while large males blow every 17.5 seconds before dives.
Brain and senses
The brain of the Sperm Whale is the largest known of any modern or extinct animal, weighing on average about . However, it is not particularly large in proportion to its body size. For example, the Sperm Whale has a lower encephalization quotient than many other whale and dolphin species, lower than that of non-human anthropoid apes and much lower than humans'.
Like other toothed whales (suborder odontoceti), Sperm Whales use echolocation as one means to find food because they live in an underwater habitat that has favourable acoustic characteristics and where visual range is limited due to absorption by water and often by suspended material. The whale emits a focused beam of high-frequency clicks covering a wide angle ahead of it. Sounds are generated by passing air from the bony nares through the phonic lips (also know as "monkey lips"), a structure within the head. The skull, melon and various air sacs in the whale's head all play important roles in forming and focusing the beam of sound. Echoes are received using the lower jaw as the primary reception path, from where they are transmitted to the inner ear via a continuous fat-filled canal.
Functions of spermaceti
The spermaceti organs may help in diving by adjusting the whale's buoyancy. Before diving, cold water is brought through the organ and the wax is solidified. The increase in specific density generates a down force of about and allows the whale to dive with minimal effort. During the chase in deep levels (max. 3,000 m) the stored oxygen is consumed and excess heat melts the spermaceti. Now only hydrodynamic forces generated by swimming keep the whale down, and it can surface without effort.
Herman Melville's Moby Dick suggests that the "case" containing the spermaceti 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.
Another 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 Sperm Whale actually has two nostrils — one external nostril, forming the blow hole, and one internal nostril pressing against the bag-like spermaceti container. The male Sperm Whale's spermaceti organ is much larger than the female's, and this dimorphism may be a case of sexual selection, enabling males to compete for the favours of females by sound displays.
Ecology, behaviour and life history
Distribution
The Sperm Whale is among the most cosmopolitan species in the world, as it is relatively abundant from polar waters to the equator., and is found in all the oceans and the Mediterranean Sea.Although both sexes range through temperate and tropical oceans and seas, only adult males move through the higher latitudes.
It can be found in most marine waters that are over deep and are not covered with ice, with the exception of the Black Sea. Its presence in the Red Sea is uncertain. Both the Black Sea and Red Sea have shallow entrances, which may account for the absence of Sperm Whales in these waters. The Black Sea's lower layers are also anoxic and contain high concentrations of sulphur compound 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 . Coastal areas with significant Sperm Whale populations include the Azores and the Caribbean island of Dominica.
Reproduction
Sperm Whales can live 70 years or more. They are a prime example of a species that has been K-selected, a reproductive strategy associated with very stable environmental conditions that is characterized by a low birth rate, significant parental aid to offspring, slow maturation and high longevity.
The manner in which it is determined which males breed with which females has not been definitively determined. There is evidence that the males have dominance hierarchies and there is also evidence that female choice influences the mating system. A single calf is born after a gestation period of 14 to 16 months. Lactation proceeds for 19 to 42 months, but the calf may suckle for up to 13 years (although usually less). Calves can suckle from females other than their mothers. Females generally have interbirth intervals of three to six years.
Females reach sexual maturity at between 7 and 13 years old, but males do not become sexually mature until at least 18 years old. Upon reaching sexual maturity, males move to higher latitudes, where the water is colder and feeding is more productive. Females remain at lower latitudes upon reaching sexual maturity.
Males only reach their full size when about 50 years old.
Social behavior
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 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 attack or harass them. Pods of Orcas target groups of females with young, usually trying to separate a calf and kill it. The female Sperm Whales can often repel these attacks by forming a circle with their calves in the centre. The adults either face inwards to use their tail flukes against the Orcas, or outwards, in which case their jaws are the principal defensive weapons. The adoption of this Marguerite formation is also used to support an injured member of the pod, a behaviour that was exploited by early whalers as they could attract a whole pod by injuring just one of the whales. If the Orca pod is extremely large, they may sometimes also kill adult females. Large bull Sperm Whales have no non-human predators, and are believed to be too large and strong to be threatened by orcas.
Feeding
Sperm whales 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 larger items. Most of what is known about deep sea squid has been learned from specimens found in captured Sperm Whale stomachs, although more recent studies have analysed fecal matter instead. One study, carried out around the Galápagos, found that squid from the genera Histioteuthis (62%), Ancistrocheirus (16%), and Octopoteuthis (7%) were the most commonly taken, and that most squid were between 12 and 650 kg in weight. Battles between Sperm Whales and colossal squid (which have been measured to weigh nearly 500 kg) have never been observed by humans, however white scars on the bodies of Sperm Whales are believed to be caused by squid. The whales usually dive between , and sometimes up to , in search of food. Such dives can last more than an hour.
An older study, examining the contents of 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. Stealing of Sablefish and Toothfish from long lines has been documented. 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. However, the amount of fish taken is very little compared to what the Sperm Whale needs per day. New video footage has been captured of a large male Sperm Whale "bouncing" a long line, to gain the fish. In one case three Sperm Whales were observed attacking or playing with a megamouth shark, a rare and large deep-sea species only discovered by man in the 1970s.
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.
It is not well understood why the Sperm Whale has such a large head in comparison to the lower jaw. One theory explaining this 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 those of seawater to reflect sounds. The Sperm Whale's head contains a structure called 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 – 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 away. It has been hypothesised that these were directed at prey in order to stun them, however experimental studies attempting to duplicate this effect have been unable to replicate the supposed injuries, and have cast doubt on this idea.
Taxonomy and naming
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, which is placed 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 sometimes also placed in this family, or else are placed in their own family, Kogiidae. In some taxonomic schemes the families Kogiidae and Physeteridae are combined as the superfamily Physeteroidea (refer separate entry sperm whale family).
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 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 widely-used in books and articles, although most recent authors now accept macrocephalus as the valid name, with catodon relegated to the status of a synonym.
Evolutionary History
Fossil record
Although the fossil record of whales is generally poor, several extinct fossil 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 (about ), is the most primitive fossil that has been found which possesses some of the features specific to the Sperm Whale lineage, such as an asymmetric rostrum ("beak" or "snout"). Most known fossils from the Sperm Whale lineage date from the Miocene period, . 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 have been 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.
Fossil sperm whales differed from modern sperm whales in the number of teeth and the shape of the face and jaws. For example Scaldicetus had a tapered rostrum. Genera from the Oligocene and ealy 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 (lower jaw). These anatomical differences suggest that fossil species may not have necessarily been deep-sea squid eaters like the modern Sperm Whale, but that at least 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 (Killer Whale).
Phylogeny
The traditional view has been that the Mysticeti (baleen whales) and Odontoceti (toothed whales) arose from more primitive whales early in the Oligocene period, and that the super-family Physeteroidea, which contains the Sperm Whale, Dwarf Sperm Whale and Pygmy Sperm Whale, diverged from other toothed whales soon after that, over . In 1993–1996 molecular phylogenetics analyses by Milinkovitch and colleagues, based on comparing the genes of various modern whales, suggested that the sperm whales are more closely related to the baleen whales than they are to other toothed whales, which would have meant that Odontoceti were not monophyletic, in other words did not consist of a single ancestral toothed whale species and all its descendants. However more recent studies, based on various combinations of comparative anatomy and molecular phylogenetics, criticised Milinkovitch's analysis on technical grounds and re-affirmed that the Odontoceti are monophyletic.
These analyses also confirm that there was a rapid evolutionary radiation (diversification) of the Physeteroidea in the Miocene period. The Kogiidae (Dwarf and Pygmy Sperm Whales) diverged from the Physeteridae (true sperm whales) at least .
Relationship with humans
Historical hunting
Spermaceti, obtained primarily from the spermaceti organ and junk, 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.
Historically, whaling took a heavy toll on Sperm Whale populations. Prior to the early 18th century, very little hunting of Sperm Whales took place, mostly by indigenous people of Indonesia. Legend has it that sometime in the early 18th century, supposed to be not far from 1712, Captain Christopher Hussey, while cruising for Right Whales near shore, was blown offshore by a northerly wind, where he encountered a school of Sperm whales and killed one. Although the story may not be true, Sperm Whales were indeed soon exploited by American whalemen, as Judge Paul Dudley, in his Essay upon the Natural History of Whales (1725), states that one Atkins, ten or twelve years in the trade, was among the first to catch Sperm Whales sometime around 1720 off the coast of New England.
Only a few Sperm Whales were recorded to have been caught during the first few decades (1709-1730s) of offshore whaling, as sloops concentrated on Nantucket Shoals where they would have taken Right Whales or were sent to the Davis Strait region to catch Bowhead Whales. By the early 1740s, with the advent of spermaceti candles (before 1743), American vessels appear to have begun to take Sperm Whales in earnest. The diary of Benjamin Bangs (1721-1769) shows that, along with the bumpkin sloop he was in, he found three other sloops with Sperm Whales being flensed alongside off the coast of North Carolina in late May 1743. On returning to Nantucket in the summer 1744 on a subsequent sperm whaling 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 (1763), the Azores (1765) and the South Atlantic (1770s). 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-1800s, as spermaceti oil was important in public lighting (for example, in lighthouses, where it was used in the United States until 1862, when it was replaced by lard oil, which was quickly replaced by petroleum) and for lubricating the machines (such as those used in cotton mills) of the Industrial Revolution. Sperm whaling declined in the second half of the 19th century, as petroleum and other products began to replace spermaceti..
Sperm whaling in the 18th century began with small sloops carrying only a pair of whaleboats (sometimes only one). The scope and size of the fleet increased over time, and eventually finally ships were introduced. In the late 18th and early 19th century Sperm Whaling boats were sent to the Pacific, the Indian Ocean, Japan, the coast of Arabia, Australia and New Zealand. Hunting for Sperm Whales could be dangerous to the crew. For example, on November 20, 1820, a Sperm Whale claimed to be about 25.9 m (85 ft) long attacked the Nantucket whaleship Essex. Only 8 out of the 21 sailors managed to survive and be rescued by other ships.
Whaling activity declined from the 1880s until 1946, but picked up again after World War II. Modern whaling was more efficient than open-boat whaling, using steam powered ships and exploding harpoons. Initially, modern whaling activity focused on large baleen whales, but as these populations were decimated, sperm whaling increased. Cosmetics, soap and machine oil formed the major used of Sperm Whale products during this time. After Sperm Whale populations declined significantly, the species was given full protection by the International Whaling Commission in 1985. Hunting of Sperm Whales by Japan in the northern Pacific Ocean continued until 1988.
It is estimated that the historic worldwide Sperm Whale population numbered 1,100,000 before commercial sperm whaling began in the early 18th century. By 1880 it had declined 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, with the industry's focus again on Sperm Whales, the population declined even further to only 33 per cent. It has been estimated that in the 19th century between 184,000 and 236,000 Sperm Whales were been killed by the various whaling nations, while in the modern era, at least 770,000 were taken, the majority between 1946 and 1980.
Remaining Sperm Whale populations are large enough so that the species' conservation status is vulnerable, rather than endangered. 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.
Current conservation status
The number of Sperm Whales throughout the world is unknown, but is thought to be in the hundreds of thousands. Although the Sperm Whale was hunted for several centuries for its meat, oil and spermaceti, the conservational outlook for Sperm Whales 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 catch the deep-sea creatures that Sperm Whales eat. However, long-line fishing operations in the Gulf of Alaska have complained about Sperm Whales stealing fish off 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" from a conservation standpoint.
Cultural importance
The teeth of Sperm Whales, when mounted on rope, are important cultural objects in Fiji, where they are known as tabua. They were traditionally given as gifts for atonement or esteem (called sevusevu), and were important in negotiations between rival chiefs. Today the tabua remains an important item in Fijian life. The teeth were originally rare in Fiji and Tonga, which exported the teeth, but with the arrival of Europeans the market was flooded with teeth and this "currency" collapsed. The oversupply led in turn to the development of the European art of scrimshaw.
The title character of Herman Melville's novel, Moby Dick, which has been described as "the pinnacle of American Romanticism" is a Sperm Whale. Melville associated the Sperm Whale with the Leviathan of the Bible. The fearsome reputation perpetuated by Melville was based on bull whales' ability to fiercely defend themselves from attacks by early whalers, sometimes resulting in the destruction of the whaling ships.
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, Andenes and Tromsø in Arctic Norway and at the Azores where it can be seen throughout the year. Dominica is believed to be the only Caribbean island with a year-round residential pod of females and calves.
Bibliography
Footnotes
- Until 1974 the species was generally known as P. catodon, however in that year Husson & Holthuis proposed that the correct name should be P. macrocephalus, the second name in the genus Physeter published by Linnaeus concurrently with P. catodon, on the grounds that the names were synonyms published simultaneously and therefore the ICZN principle of "First Reviser" should apply, in this instance leading to the choice of P. macrocephalus over P. catodon, a view re-stated in Holthuis, 1987. This has been adopted by most subsequent authors, although Schevill (1986 and 1987) argued that macrocephalus was published with an inaccurate description and that therefore only the species catodon was valid, rendering the principle of "First Reviser" inapplicable. At the present time, the name P. catodon is used in the , however this is expected to be changed to follow the most recent version of which has recently altered its usage from P. catodon to P. macrocephalus following L. B. Holthuis, and recent (2008) discussions with relevant experts (refer cited ITIS page for additional information).
External links
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- Photographs, video.
- exploring the Sperm Whales of Greece.
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