Marine Mammal Species Description

Dwarf Sperm Whale

Kogia sima

(Owen, 1866)

Classification

Order: Cetacea
Family: Kogiidae
Alternate Common Names:

Status: protected under MMPA

Description:

   Length: 6.9-8.9 ft (2.1-2.7 m)
   Weight: 300-600 lbs (136-272 kg)

Dwarf sperm whales are dark gray or bluish gray above that fades to a light-gray or white on their undersides. They have a crescent-shaped pigmentation pattern behind the eye that looks like a gill slit. They are robust shaped and have a large bulbous head that protrudes beyond their underslung lower jaw. They have a relatively large falcate dorsal fin that is just behind or near the middle of their back. Dwarf sperm whales have 7-12 pairs of teeth in their lower jaw and up to 3 pairs in their upper jaw.

Habitat:

Dwarf sperm whales occur in warmer deep waters near the continental shelf. This species occurs by itself or in schools of 2-10 individuals.

Feeding:

Dwarf sperm whales eat mostly squid, but also eat some fish and crustaceans. They have been recorded diving up to 984 ft (300 m).

Reproduction:

Both male and female dwarf sperm whales reach sexual maturity around 6.9 ft (2.1 m) in length.

Other:

The dwarf sperm whale was separated from its close relative, pygmy sperm whales, in 1966. These two species are very difficult to tell apart. Observers rarely see this species in the wild; therefore, information about it is limited. Like an octopus, dwarf pygmy whales use a defense mechanism to conceal their location by clouding the water. They defecate; this large amount of reddish-brown feces in the water blurs the view of a potential predator. After defecating, they typically dive away.

Distribution / Range:

These whales occur in temperate and tropical waters worldwide. Off the coasts of the United States, it is documented from most of the east and west coast including the Gulf of Mexico. It tends to be more common in warmer, more southern areas off the coast of the United States.

Similar species:

The most similar species is the pygmy sperm whale, Kogia breviceps. Pygmy sperm whales are larger and have a smaller dorsal fin. These two species also have a different number of teeth (10-16 pairs in K. breviceps and 7-12 pairs in K. simus). These two species are difficult to tell apart in the wild, even by professionals.

Notes:

References:

Birchler, B. and C.W. Porter. 1999. Dwarf sperm whale, Kogia simus. In The Smithsonian Book of North American Mammals. Wilson, D.E. and S. Ruff, eds., 302-303. Smithsonian Institution in association with the American Society of Mammologists, Washington DC.

Culik, B. 2010. Odontocetes. The toothed whales: "Kogia sima". UNEP/CMS Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm. Accessed January 2012.

Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. 2008. Kogia sima. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. www.iucnredlist.org. Downloaded on 09 January 2012.