Only one young is born at a time. Gestation lasts for 10 to 11 months. Weight at birth is 450 kg. The young are weaned at 5 months, but they do not become sexually mature for 6 years. Females are thought to have young every other year. The breeding period is long--from December to May in the Atlantic and year round in the Pacific. Peak months for births are December and June. Growth stops at about 18 years for females and 20 years for males.

Breeding interval: Females are thought to have young every other year.

Breeding season: The breeding period lasts from December to May in the Atlantic and year round in the Pacific

Average number of offspring: 1.

Range gestation period: 10 to 11 months.

Average age at sexual or reproductive maturity (female): 6 years.

Average age at sexual or reproductive maturity (male): 6 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average birth mass: 320000 g.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 2740 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 2740 days.