Pygmy Sperm Whale


Pygmy Sperm Whale

Family: Physeteridae
Genus: Kogia
Species: K. breviceps   (deBlainville, 1838)

The pygmy sperm whale is one of three members of the family Physeteridae and has certain basic similarities to the sperm whale. Both have an underslung, small lower jaw containing the only functional teeth, an asymmetrical blowhole placed slightly to the left of the forehead, a spermaceti organ, and many skeletal similarities. Also, like the sperm whale, pygmy sperm whales are not coastal animals; indeed, their deep-sea distribution and the fact that they were never the prey of industrial whalers makes them very little known. They are slow and deliberate swimmers and can easily be approached by boats when encountered at sea. Most of what we know about this species comes from animals which have washed up on shore alive and been taken to marine parks for observation. None has survived more than a couple of weeks in captivity. The pygmy sperm and the dwarf sperm whale formerly were considered one species.

Physical Description: This whale has a very stocky body. The head is squared with the lower jaw, hinged well behind the snout.  A single blowhole is located slightly to the left of the forehead. The caudal peduncle tapers abruptly to the flukes.

Color: The dark brown-black dorsal side gradually fades to light ventral flanks. Behind the eyes a dark patch resembling a fish’s gill cover extends the height of the head region.

Fins and Flukes: A tiny falcate dorsal fin is located to the rear of the mid-back region. The flippers are large and slightly rounded at the tips with straight leading edges and convex trailing edges. The flukes are large and slightly rounded at the tips, with a definite median notch.

Length and Weight: Pygmy sperm whales reach 11 ft (3.4 m) and may exceed 900 lb (400 kg).

Teeth: There are 10 to 16 long, curved, needle-sharp teeth in each side of the lower jaw, fitting into sockets in the upper jaw. There are no teeth in the upper jaw.

Feeding: These whales feed mostly on octopus and squid, but also take small fish, crabs and other invertebrates.

Breathing and Diving: They rise slowly to the surface to breathe, blowing inconspicuously. They do not roll forward at the surface as do most small whales.

Mating and Breeding: Calves, 4 ft (1.2 m), are thought to be born in late spring after an 11-month gestation period. Males are sexually mature at 9 to 9.75 ft (2.7 to 3 m), females at 8.5 to 9 ft (2.6 to 2.7 m).

Herding: Individually, or in groups of 2 or 3.

Distribution: They are found worldwide in tropical and warm temperate waters.

Migration: No information available.

Natural History Notes: This is a very shy animal that will not itself approach boats, but on calm days a boat can approach closely as the animals lie quietly on the surface looking much like logs with dorsal fins.

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