Dolphin reproduction starts when a couple of dolphins mate.
The copulation occurs belly to belly initiating the gestation period which varies according to the species but ranges from 11 to 17 months in the case of the killer whale, being 12 months for the common bottlenose dolphin.
Dolphin mothers usually go to shallow waters to deliver their offspring, sometimes assisted by another dolphin which takes the role of a midwife.
Commonly, a single calf is born, and for around 18 months the mother nourishes it with milk produced by her body.
Calves stay in the pod and close to their mothers for around six years.