However, he dismissed the term as an imprecise leftover from an era when almost all biologists were male. The modern view of the sperm whale lifestyle recognizes that females spend their lives swimming in tropical or near tropical waters in pods with young of both sexes. Males eventually peel away from the pod, sometimes joining bachelor groups for while. They mature into solitary adults, cruising farther and farther north toward the Arctic and Antarctic. A male journeys back to the tropics to mate every five or six years, according to the current estimate.
Researchers now have evidence about what happens next, thanks to the new genetic analysis.
A visiting male seems to mate with several of the females in a particular pod before moving on to another pod. The new analysis also confirmed that the youngsters in a pod are related to the adult females, as if several moms and their kids started swimming together for a while. And for the first time, researchers have genetic evidence about when the males leave, which seems to be at age five or six. This information of kinship may help the biologists who study so- called altruism in animals, Wright said. Whales indeed do things that would be called altruistic in a human, including suckling the baby of another female as well as babysitting and defending other female whales' offspring.