SPERM WHALE

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© Larry Foster, Earth Views

Physeter macrocephalus (= P. catadon)

Federal Status: Endangered (June 2, 1970)
State Status: Endangered (December 20, 1989)

Description: The enormous head (25-30% of total length) is rectangular in profile; lower jaw small, narrow, shorter than snout. Dorsal fin replaced by a hump with several ridges on the posterior portion of the back. Flippers are relatively small but flukes are broad. Single blowhole on tip of snout, located left of midline. Overall body color steel-gray with some blotches on lower jaw, belly and sides. Twenty to 25 large conical teeth in each side of lower jaw. Adult males may reach 20 m (65.6 ft) total length although individuals larger than 18 m (59 ft) are rare; females rarely exceed 12 m (40 ft). Travels in herds of up to 30 mature females and nursing calves led by an adult male or in small groups of bachelor males; however groups of up to 1,000 individuals have been reported. Males move into higher latitudes, often to the edge of polar ice, while females and young stay in warmer waters (between 40 degrees north and 40 degrees south latitude). One (rarely 2) calves born every 4 years. Eats mostly squid, especially deep-water species; also fish and crustaceans. May dive to depths in excess of 3,000 m (10,476 ft) when feeding. The head of the sperm whale contains the spermaceti organ, which is a large reservoir for spermaceti oil. Sperm whales are hunted for this oil, as well as the lower grade oil contained in the blubber.

Habitat: Marine deepwater.

Distribution: Found in oceans worldwide, generally beyond the continental shelf. Most sightings from the Gulf are from beyond the 1,000 fathom line, although strandings have occurred throughout the Gulf coast. Individual strandings have been documented from Cameron, Terrebonne and Plaquemines parishes but there have been numerous recent sightings off the mouth of the Mississippi River.

Reasons for decline: Overharvest.

March 2004

Conservation efforts:

1. Monitor world's population.
2. Determine pregnancy rates, natural mortality rate, age at recruitment, and reserve male ratio.