It is the only living member of genus Physeter and one of three extant species in the sperm whale family , along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia. The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. 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, although calves and weakened adults are sometimes killed by pods of orcas killer whales.