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The sperm whale is the largest of the toothed whales and can reach a length of 65 feet. Its massive round head accounts for about one third of its total body length. It is believed that the sperm whale dives deeper than any other marine mammal and may reach depths of more than 10,000 feet although the deepest recorded dive is 4,000 feet. A large bull whale can dive deepest and for the longest period of time, staying underwater for up to 45 minutes.

The sperm whale is a sociable animal that lives in groups. The group structure varies according to the age and sex of the whale. Males generally live apart from females. The females form groups together with their young, numbering from five to thirty animals. The whales, swim, dive, feed, and sleep together within their group. In summer, the whales migrate to feed in the Arctic and Antarctic.

The sperm whale feeds on bottom dwelling organisms, such as squid. Sometimes, giant squid put up such a struggle that scars are made on the whale’s head by its tentacles. The sperm whale will also eat snapper, lobster, and even shark. It swallows its prey whole. An adult whale will eat up to 1 ton of food every day.

Groups of sperm whales begin their migration to the equator from the Arctic and Antarctic every fall for the winter breeding season. The bulls attempt to form harems of up to 30 adult females. Fierce fights between rival males for females are not uncommon. Once the harem is established, the bull mates with any female not already pregnant or with young. After mating, the female gives birth 14-16 months later. The other females protect her while she is giving birth, and then help the calf to the surface to take its first breath. The mother feeds her calf with fat rich milk for as long as two years, by which time it has grown to a length of 23 feet.

The sperm whale has been ruthlessly hunted by man for centuries, and continues to be persecuted. Whalers have taken advantage of the whale’s protective instinct, whereby all members of a group will surround an injured animal, whalers harpoon a single sperm whale to attract other whales who come it its rescue and then kill them as well. Man hunts the sperm whale for food, and for the oil its blubber provides. Despite protection from the International Whaling Commission, numbers have dropped from 170,000 males and slightly fewer females to only 71,000 males and 125,000 females.