The mating pattern of these dolphins is promiscuous, adult males competing for mating access to females (Evans 1987). Pair bonds do not appear to be formed, but social cohesion within the school seems strong (Dawson 1985).

Mating System: polygynandrous (promiscuous)

Mating of dusky dolphins usually takes place during spring. Gestation lasts for 11 months, and the peak months of birth for dusky dolphins are June to August. Dusky dolphins produce one young per birth; the weight of the young is about 5 kg (Nowak 1991). The lactation period lasts for 18 months (Evans 1987). There is no information on the sexual maturity and the life span of dusky dolphins.

Breeding season: Mating of dusky dolphins usually takes place during spring.

Average number of offspring: 1.

Average gestation period: 11 months.

Average weaning age: 18 months.

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