Research in aquariums indicates that females become sexually mature at around 9 to 10 years of age, and it is believed that wild females give birth to their first calf between the ages of 11 and 17. Males between the ages of 12 and 13 show a noticeable growth in their dorsal fins but do not reach full size until their late teens or early twenties. Females may give birth as frequently as every three years, but may wait as long as eight years. This coloration changes to white at about one year of age. Over the first few days following birth, the dorsal fin and tail flukes of the calf begin to gradually stiffen.
Calves swim close to their mothers and are carried in the mother's slip stream.
The cow's swimming pattern creates a hydrodynamic wake, which pulls the calf along, and allows the calf to swim with less energy, which helps the pair keep up with the pod. The calf nurses from nipples concealed in two mammary slits on the underside of its mother. Calves nurse below the water, close to the surface. The mother glides in a horizontal position, and the calf swims on its side with its mouth on one of the mammary glands. Observations in aquariums have revealed that calves nurse for about five to ten seconds at a time, several times an hour, around the clock.