Sperm Whale

The sperm whale can be found anywhere in the open ocean. Females and young males live together in groups while mature males live solitary lives outside of the mating season. The females cooperate to protect and nurse their young. Females give birth every four to twenty years, and care for the calves for more than a decade. A mature sperm whale has few natural predators. Calves and weakened adults are taken by pods of orcas.

From the early eighteenth century through the late 20th the species was a prime target of whalers. The head of the whale contains a liquid wax called spermaceti, from which the whale derives its name. Spermaceti was used in lubricants, oil lamps, and candles. Ambergris, a waste product from its digestive system, is still used as a fixative in perfumes. Occasionally the sperm whale's great size allowed it to defend itself effectively against whalers. The species is now protected by a whaling moratorium, and is currently listed as vulnerable by the IUCN.

Sperm Whale
  • Size

    The sperm whale is the largest toothed whale, with adult males measuring up to 20.5 metres (67 ft) long and weighing up to 57,000 kilograms (56 long tons; 63 short tons).

    It is among the most sexually dimorphic of all cetaceans. At birth both sexes are about the same size, but mature males are typically 30% to 50% longer and three times as massive as females.

  • Feeding

    Sperm whales usually dive between 300 to 800 metres (980 to 2,620 ft), and sometimes 1–2 kilometres (3,300–6,600 ft) to search for food. Such dives can last more than an hour. They feed on several species, notably the giant squid, but also the larger colossal squid, octopuses, and diverse fish like demersal rays, but the main part of their diet consists of medium-sized squid. Some prey may be taken incidentally while eating other items.

  • Life History

    How they choose mates has not been definitively determined. Males will fight with each other over females, and males will mate with multiple females, but they do not dominate the group like a harem. Males do not provide paternal care to their offspring.

    Females become fertile at around 9 years of age. The oldest pregnant female ever recorded was 41 years old. Gestation requires 14 to 16 months, producing a single calf. Sexually mature females give birth once every 4 to 20 years (pregnancy rates were higher during the whaling era). Birth is a social event, as the mother and calf need others to protect them from predators. The other adults may jostle and bite the newborn in its first hours. Calves may be allowed to suckle from females other than their mothers. Sperm whales can live 70 years or more.

  • Behavior

    Adult males who are not breeding live solitary lives, whereas females and juvenile males live together in groups. Females and their young remain in groups, while mature males leave their "natal unit" somewhere between 4 and 21 years of age. Mature males sometimes form loose "bachelor groups" with other males of similar age and size. As males grow older, they typically live solitary lives. Mature males have beached themselves together, suggesting a degree of cooperation which is not yet fully understood. The whales rarely if ever leave their group.

    Sperm whales are not known for forging bonds with other species, but it was observed that a bottlenose dolphin with spinal deformity had been accepted into a pod of sperm whales. They are known to swim along with other whales such as humpback, finback, minke, and orca on occasion.