Neophocaena phocaenoides reaches sexual maturity by the age of 2. Reproductive cycles differ among geographic groups such as those located near Japan and those near China. The breeding cycle is 1-2 years and gestation lasts between 10 and 11 months. Births occur between February and August and there is usually 1 young per birth. Newborns are around 25kg and are weaned between September and June. Neophocaena phocaenoides has been found to live up to 23 years. (Bryden & Harrison 1986, Nowak 1991).

Breeding interval: The breeding cycle is 1-2 years

Average number of offspring: 1.

Range gestation period: 10 to 11 months.

Range weaning age: 7 to 10 months.

Range age at sexual or reproductive maturity (female): 2 (high) years.

Range age at sexual or reproductive maturity (male): 2 (high) years.

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

Average birth mass: 7000 g.

Average number of offspring: 1.

Mothers carry their offspring on a patch of skin on the dorsal surface which is covered with horny papillae. This acts like a saddle on which the young can attach and be carried. Although obviously for carrying young, the horny papillae contain nerve endings and may be a means of auxillary orientation. This "extra" means of orientation could be very beneficial to N. phocaenoides since it often lives in murky waters.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)