The star of Moby Dick, great sperm whales hold many records, including deepest diving mammal, largest toothed whale and biggest brain.

Subspecies
None.

Life span
Unknown.

Statistics
Body length: 11-18m, Weight: Males: 40-50 tonnes, Females only weigh about 1/3 as much a male.

Physical description
Sperm whales have a huge, square head (up to a third of the total body length), which is filled with a waxy substance called spermaceti oil. This is thought to be an adaptation to deep dives. They have dark, wrinkled skin with a low hump in place of a dorsal fin. They have numerous thick, conical teeth to help them grab hold of prey.

Distribution
Sperm whales are found in all the oceans except the Arctic.

Diet
Sperm whales mainly feed on squid, including giant squid - the largest invertebrate in the world - although they will also feed on octopus, deep-water fish, sharks and skate.

Behaviour
Sperm whales live in groups of 1-50 individuals and are very deep divers, reaching depths of 1000m.

Conservation status
Sperm whales are listed as Vulnerable by the 2000 IUCN Red List.

Records
Sperm whales hold many records: they can dive deeper than any other mammal in the world. Commonly a dive averages 300-600m, but they can reach 2000m, and possibly 3000m. They are thought to be able to survive underwater for two hours without coming up for a breath. They hold the record for the world's heaviest brain, despite the fact that their brains are small in comparison to their body size. They are the largest toothed whales, a group which includes dolphins, porpoises, orcas, pilot whales, narwhals and belugas.