In cetaceans, the order that includes all whales, dolphins and porpoises, females are called cows. Males are called bulls, and their offspring are called calves. Calves remain with their mothers for up to two years, depending on the species.
Cows birth their calves fluke-first, known as a breech birth, and the calf must immediately swim up to the surface for its first breath of air. In highly social species of cetaceans, such as killer whales and beluga whales, calf rearing is a shared responsibility in the family unit, which is called a pod. Also, cows fill the leadership role in pods, and sexually mature bulls – especially those that are not associated with the pod - are shunned until breeding season.