Sperm Whales

Sperm Whale (Physeter macrocephalus)

The Sperm Whale is found in all oceans of the world, and, although well-known in the Mediterranean, rarely enters semi-enclosed or shallow seas. Males venture into the extremes of the Northern and Southern Hemispheres more frequently than females ever do. In summer they migrate to higher latitudes in both hemispheres but return to lower latitudes in winter, though some populations are resident all year round.

Classification: The Sperm Whale, Physeter macrocephalus, was classified by Linnaeus, with Physeter meaning 'blower' (referring to the whale's forceful, singular spout). There is, however, some disagreement about whether the Sperm Whale's specific name should be macrocephalus (meaning 'big head') or catodon (meaning 'teeth only in lower jaw'), although the former is generally accepted.

Local Names: Cachalot; Kaskelot; Cachalote; Great Sperm Whale. This cetacean's common name is derived from the milky wax substance in its head which early whalers likened to the fluid produced by the testes to carry sperm.

Description: Made famous by Herman Melville's Moby Dick, this is the species most people associate with the word 'whale'. The largest of the toothed whales, it is dark brown to dark grey in colour, with occasional albino and black individuals being recorded. The skin is wrinkly and may be scarred. Although the triangular tail flukes are broad and powerful, flippers are short and stubby, and the dorsal fin is usually more akin to a series of humps down the tail stock's ridge than an actual 'fin'. The Sperm Whale's head is over a third of the total body length of the animal, and is well-known for being big and bulky and barrel-shaped. Males are 15-20.5m in length and weigh between 45-57 tonnes, with females measuring 11-13m and weighing around 20 tonnes. The lower jaw holds approximately 50 rounded teeth in two parallel rows, each tooth weighing over a kilogram.

Recognition at sea: Sperm Whales show little of themselves above the surface, appearing as a large 'log', often lying motionless. Their blow is one of the most recognisable of all cetaceans: single, bushy, about 5m and projecting to the forward-left of the animal.

Habitat: Sperm Whales normally only venture close to shore when the depth of the water increases rapidly away from the coast (as it does around volcanic islands), or when ill. Other than this, they are mainly oceanic creatures, with males withstanding virtually all temperatures from extreme cold to extreme warm, although females remain in areas with a surface temperature of 15°C or more.

Food & Feeding: In most areas, Sperm Whales feed on squid and octopi alone, often taking prey at considerable depths. In other areas, fish - including sharks, rays, cod, redfish and laternfish are also taken. Krakens, or giant squids, are also prey to this huge animal. Floating debris is also ocassionally ingested.

Behaviour: The family group of around 10-20 individuals is the basic social unit, consisting mainly of mature females (cows) with their calves. The females remain in this tight-knit family throughout their lives, from birth to death, whereas young males leave at puberty to join a pod of medium-sized 'batchelors'. As they get older, the males (bulls) become more anti-social and may eventually become the solitary individuals seen in cold temperate and polar waters. Often Sperm Whales gather together, en masse, in groups of hundreds and even thousands, covering an area of many kilometers but obviously travelling as a unit. The deepest and longest-diving of all cetaceans, the Sperm Whale can remain below the surface for around 90minutes, at depths of 1,100-3,200m. They communicate via pulsed clicks, and it has been theorised that some of these clicks are so powerful that they are used to 'stun' their prey.

Longevity: Approximately 70 years.

Estimated Current Population: Approximately 2,000,000 animals.

The Influence of Man: Sperm Whales were killed mainly for the oil produced from their thick blubber, and for the wax found in the head - known as spermaceti. Originally used for purfume, ambergris also came from this species of whale; and the black, oily meat of the Sperm Whale was never taken for food, except by a few communities. This cetacean has been killed every year from around 1690-1987, with the heavy commercial fishery beginning in earnest in the early Eighteenth Century. Hundreds of thousands had been killed in all oceans of the world, with a peak in the 1963/64 whaling season of 29,300 individuals. In 1971 the first International Whaling Commission restrictions were enforced, and by 1984 all commercial Sperm Whale catches were banned. Sperm Whales are now common whale-watching attractions, especially in the waters around New Zealand.

Pygmy Sperm (Kogia breviceps)

The Pygmy Sperm Whale is widely distributed in tropical, sub-tropical, and temperate seas. Records of sightings are scattered from Ireland and the Netherlands down the North Atlantic to the Canary Islands and Madiera, and from Nova Scotia to Cuba. Other sightings have been recorded in the South Atlantic, the Indian Ocean, and the Indo-Pacific.

Classification: The Pygmy Sperm Whale, Kogia breviceps, was classified by the Compte de Blainville in 1838, one of two species recognised in this genus. The specific name, breviceps, means 'short-headed'.

Local Names: Lesser Sperm Whale; Short-Headed Sperm Whale; Lesser Cachalot.

Description: This robust whale is really a smaller version of the Sperm Whale, with the same large, bulbous head containing spermaceti and the short narrow mouth. The snout is pointed in young animals but reverts to the familiar rectangular shape in adulthood. The slightly-hooked dorsal fin and the flippers are small and stumpy, and the broad tail flukes are less rigid than those of dolphins. The body colour is a dark bluish grey, fading to a slightly pinkish off-white underneath. A thin whitish line runs downwards from behind the eye and the external ear to the throat, appearing as a false 'gill'. Maximum weight is 400kg, and a maximum length of 3.3m is attained in both sexes. There are no teeth in the upper jaw, but around 24-32 in the lower.

Recognition at sea: The Pygmy Sperm Whale can be easily confused with Beaked Whales and the Dwarf Sperm Whale. However, Beaked Whales can usually be distinguished by their larger size, more rapid movement and - at close range - their elongated snout. The Pygmy Sperm Whale has a smaller dorsal fin than the Dwarf Sperm, and, when stranded, can be confused with a shark at first glance.

Habitat: Pygmy Sperm Whales are oceanic animals, moving across and over the continental shelf to feed.

Food & Feeding:This species of cetacean is slow-moving and hunts by stealth, so prey are probably incapable of fast movement. Primarily the Pygmy Sperm Whale eats small fish, cuttlefish, deepsea shrimps and squid.

Behaviour: There have been very few observations of the Pygmy Sperm Whale, and these suggest that it is a sluggish and slow-moving animal. The blow is inconspicuous and low, and after blowing the cetacean simply drops out of sight. It rarely approaches boats, and when startled evacuates a reddish-brown intestinal fluid as a decoy before it dives. Pods contain less than ten individuals.

Longevity: Unknown.

Estimated Current Population: Unknown.

The Influence of Man: Small numbers of the Pygmy Sperm Whale are killed by Japanese and Indonesian small whalers, but these killings are not thought to influence world population levels. However, larger numbers of this small cetacean - and many others - are caught in gill-nets, for example, off Sri Lanka.

Dwarf Sperm (Kogia simus)

The Dwarf Sperm Whale is widely distributed through tropical and temperate seas. Records of sightings are scattered along the American coast of the North Atlantic, the South American and African coasts of the South Atlantic, the Indo-Pacific region and the Pacific ocean as a whole.

Classification: The Dwarf Sperm Whale, Kogia simus, although described by the English anatomist Owen in 1866, was only accepted as a species separate to Kogia breviceps (the Pygmy Sperm Whale) a century later. The scientific name, simus, refers to the snubbed snout.

Local Names: Owen's Pygmy Sperm Whale.

Description: This robust cetacean is the smallest of all whales, and closely resembles the Pygmy Sperm Whale in size, stature and colour. However, the snout of the Dwarf Sperm Whale becomes blunt and square, not rectangular, in adulthood, and the dorsal fin is larger. There are a number of small irregular grooves on the throat behind the mouth. There are between fourteen and twenty-four teeth on the lower jaw, with up to three pairs on the upper. They are dark bluish grey in colour, lightening to a pinkish off-white underneath. Maximum weight is around 210kg, with a maximum length of 2.7m being attained in both sexes.

Recognition at sea: The Dwarf Sperm Whale can be easily confused with the Pygmy Sperm Whale, and other blunt-headed cetaceans (such as Risso's Dolphin, the Pygmy Killer Whale and the Melon-Headed Whale). However, the Dwarf Sperm Whale has a more square-shaped head and moves much slower than the other species of blunt-headed cetacean, and it has a larger dorsal fin than the Pygmy Sperm Whale.

Habitat: Dwarf Sperm Whales are oceanic animals, moving across and over the continental shelf to feed.

Food & Feeding: Like the Pygmy Sperm Whale, this species of cetacean is slow-moving and hunts by stealth, so prey are probably incapable of fast movement - therefore, again like the Pygmy Sperm Whale, the Dwarf Sperm Whale eats small fish, cuttlefish, deepsea shrimps and squid.

Behaviour: Pods contain less than ten animals, mainly females with calves and sexually immature males. The behaviour of the Dwarf Sperm Whale is very similar to that of the Pygmy Sperm Whale. The blow is inconspicuous and low, and after blowing the cetacean simply drops out of sight. It rarely approaches boats, and when startled evacuates a reddish-brown intestinal fluid as a decoy before it dives.

Longevity: Unknown.

Estimated Current Population: Unknown.

The Influence of Man: Small numbers of the Dwarf Sperm Whale were taken by early whalers, and a few have been taken in recent years by Japan and the Caribbean. Again akin to the Pygmy Sperm Whale, larger numbers of this small cetacean are caught in gill-nets.

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