Pygmy Sperm Whale

Classification

Class: Mammalia
Order: Cetecea
Suborder: Odontoceti
Family: Kogiidae
Genus: Kogia
Species: breviceps
Common Names: Pygmy sperm whale
Irish Name: Caisealóid bheag
 

Key Identification Features

Maximum body length: Adult male 3.4m
Average body length: Adult length 2.7 – 3.4m
Blow: Low and conspicuous
Head shape: Square or conical shark-like head with tiny underslung lower jaw.
Beak: Inconspicuous, teeth long, sharp and pointed inward, 24 – 36 in the lower jaw only.
Dorsal fin: Tiny but falcate, located aft of mid-back.
Colouration: Dark bluish grey back, lighter down sides to white belly. Pale crescent-shaped “false gill” on each side between the eye and flipper.
Body: Short, robust body. Short flippers located far forward. Body may appear wrinkled. Blowhole left of centre.
 

Field Identification

At sea, pygmy sperm whales are likely to be confused with only the beaked whales, which have small dorsal fins or dwarf sperm whales (Kogia simus) which do not occur in the NE Atlantic. They are deep and long diving and after surfacing, sink inconspicuously without rolling and are seldom resighted.

Species Similar in Appearance

Most likely to be confused with beaked whales in the Atlantic.

Behaviour

Solitary or in small groups. There are few observations at sea but from the little information available, they may be approached and have been startled while floating motionless at surface. When startled, often excrete an ink-like substance, darkening the surrounding water. It is not regarded as a fast swimmer.

Status and Distribution

The pygmy sperm whale appears to be cosmopolitan, recorded from nearly temperate, subtropical and tropical waters. Most of the information is from strandings records, and appear to be common off the south-eastern United States, where they are the second most frequently stranded cetacean. In the last 10 years there has been two reported strandings of this species on the west coast of Ireland. Nothing is known about abundance or stock discrimination.

Food and Feeding

Kogia breviceps is considered a pelagic species, living over the continental shelf edge, slope and deep oceanic waters. Their diet includes oceanic squid and cuttlefish, fish and crustaceans.

Reproduction and Life Cycle

Female sexual maturity: 2.6 - 2.8m length
Gestation period: 11 months
Calves born: 1.2m
Male sexual maturity: 2.7 - 3.0m in length

Conservation Issues

Small numbers are killed by Japanese and Indonesian small whalers for food. Incidental mortality in fishing gear has been documented off Sri Lanka.

Ship strikes may be a cause for concern in the US
 

ID image

pygmysperm.jpg

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