Pygmy sperm whale
Pygmy sperm whales are found throughout the tropical and temperate waters of the Atlantic, Pacific and Indian Oceans.
The pygmy sperm whale (Kogia breviceps) is one of three species of toothed whale in the sperm whale family. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.
There has been debate and differing opinion as to the correct classification of the pygmy and dwarf sperm whales (see sperm whale family for details). The two were widely considered to be the same species, until 1966, when a scientist at the Smithsonian Institution definitively identified them as separate species. The pygmy sperm whale was first named by Henri Marie Ducrotay de Blainville in 1838.
The pygmy sperm whale is not much larger than many dolphins. They are about 1.2 metres (3 ft 11 in) at birth, growing to about 3.5 metres (11 ft) at maturity. Adults weigh about 400 kilograms (880 lb). The shark-like head is large in comparison to body size, given an almost swollen appearance when viewed from the side.
Analysis of stomach contents suggests that pygmy sperm whales feed primarily on cephalopods, most commonly including bioluminescent species found in midwater environments. The most common prey are reported to include glass squid, and lycoteuthid and ommastrephid squid, although the whales also consume other squid, and octopuses. They have also been reported to eat some deep-sea shrimps.
Although firm details concerning pygmy sperm whale reproduction are limited, they are believed to mate from April to September in the southern hemisphere.Gestation lasts eleven months and, unusually for cetaceans, the female gives birth to the calf head-first. Newborn calves are about 1.2 metres (3 ft 11 in) in length, and are weaned at around one year of age.
Pygmy sperm whales are normally either solitary, or found in pairs but have been seen in groups of up to six. Dives have been estimated to last an average of eleven minutes, although longer dives of up to 45 minutes have been reported.The ultrasonic clicks of pygmy sperm whales range from 60 to 200 kHz, peaking at 125 kHz, and the animals also make much lower frequency
"cries" at 1 to 2 kHz.