Physeter breviceps de Blainville, Kogia breviceps Gray, First use of current name combination. Euphysetes Grayii Wall, Kogia grayii Gray,
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Taxonomy[ edit ] Illustration from the 19th century The pygmy sperm whale was first described by naturalist Henri Marie Ducrotay de Blainville in He recognized it as a type of sperm whale and assigned it to the same genus as the sperm whale Physeter macrocephalus as Physeter breviceps. In , naturalist James Hector synonymized the dwarf sperm whale with the pygmy sperm whale, with both being referred to as K. They are about 1. The underside is a creamy, occasionally pinkish colour and the back and sides are a bluish grey; however, considerable intermixing occurs between the two colours.
The shark-like head is large in comparison to body size, given an almost swollen appearance when viewed from the side. A whitish marking, often described as a "false gill", is seen behind each eye. The blowhole is displaced slightly to the left when viewed from above facing forward. The dorsal fin is very small and hooked; its size is considerably smaller than that of the dwarf sperm whale and may be used for diagnostic purposes.
Anatomy[ edit ] Closeup of the head Like its giant relative, the sperm whale , the pygmy sperm whale has a spermaceti organ in its forehead see sperm whale for a discussion of its purpose. It also has a sac in its intestines that contains a dark red fluid. The whale may expel this fluid when frightened, perhaps to confuse and disorient predators.
Each of the flippers has seven carpals , and a variable number of phalanges in the digits, reportedly ranging from two in the first digit to as many as 10 in the second digit. No true innominate bone exists; it is replaced by a sheet of dense connective tissue. Teeth[ edit ] The pygmy sperm has between 20 and 32 teeth, all of which are set into the rostral part of the lower jaw. The inner core transmits sound more slowly than the outer layer, allowing it to refract sound into a highly directional beam.
Both the melon and the spermaceti organ are encased in a thick fibrous coat, resembling a bursa. Note that the view pictured on the right is an axial view, not coronal as noted Stomach[ edit ] The stomach has three chambers. The first chamber, or forestomach, is not glandular, and opens directly into the second, fundic chamber, which is lined by digestive glands. A narrow tube runs from the second to the third, or pyloric, stomach, which is also glandular, and connects, via a sphincter , to the duodenum.
Although fermentation of food material apparently occurs in the small intestine , no caecum is present. Sound produced for echolocation by many odontocetes come in the form of high frequency clicks. Fat on the interior of the melon has a lower molecular weight lipid than the surrounding outer melon. Variation in fat density within the melon ultimately contributes to the production of highly directional, ultrasonic sound beams in front of the melon.
Like in most odontocetes, the known echoreception apparatus used by the pygmy sperm whale is linked to the fat-filled lower mandibles within the skull.
See also: Whale reproduction Although firm details concerning pygmy sperm whale reproduction are limited, they are believed to mate from April to September in the Southern hemisphere and March to August in the Northern hemisphere.
Once a female whale is impregnated, the average gestation period lasts nine to eleven months and, unusually for cetaceans , the female gives birth to a single calf head-first. Behaviour[ edit ] The whale makes very inconspicuous movements. It rises to the surface slowly, with little splash or blow, and remains there motionless for some time. In Japan , the whale was historically known as the "floating whale" because of this. Its dive is equally lacking in grand flourish - it simply drops out of view.
The species has a tendency to back away from rather than approach boats. Breaching has been observed, but is not common. Most of the cephalopod hunting is known to be pelagic, and fairly shallow, within the first m of the surface. They have also been reported to eat some deep-sea shrimps , but, compared with dwarf sperm whales, relatively few fish. Both species have a sac in the lower portion of their intestinal tract that contains up to 12 liters of dark reddish-brown fluid, which can be ejected to confuse or discourage potential predators.
The total population is unknown. Fossils identified as belonging to K. Land-based whalers have hunted them from Indonesia , Japan , and the Lesser Antilles. This species was impacted by whaling in the 18th and 19th centuries, as sperm whales were especially sought after by whalers for their sperm oil, produced by the spermaceti organ.
The oil was used to fuel kerosene lamps. Ambergris , a waste product produced by the whales, was also valuable to whalers as it was used by humans in cosmetics and perfume. However, they were easy targets, as they tended to swim slowly and lie motionless at the surface.
Some stranded animals have been found with plastic bags in their stomachs - which may be a cause for concern. It is not known whether these activities are causing long-term damage to the survival of the species. Pygmy sperm whales do not do well in captivity. It is one of the most common stranded species in Florida sound. Due to its slow moving and quiet nature, the species is at a higher risk of boat strikes.
Wie bei allen Pottwalen ist das Blasloch auf die linke Seite verschoben. Ein heller Streifen zieht sich auf jeder Seite von den Augen zu den kurzen, breiten Flippern , die konvex gebogen sind. Die breiten Flukenteile laufen zum Ende spitz aus. Manchmal sieht man sie auch bewegungslos im Wasser treiben. Diese Wale leben entweder allein oder in kleinen Gruppen von drei bis sechs Tieren, ihre Nahrung besteht vorwiegend aus Tintenfischen und Krebstieren.
Pygmy sperm whale