Arctocephalus forsteri females reach sexual maturity between 4 and 6 years of age, and males become sexually mature near 5-6 years old. The breeding season within this species begins in mid-November and lasts through mid-January. New Zealand fur seals are polygamous, with 1 male mating with several females. Females give birth to 1 pup nearly every year until their death around 14-17 years. Females mate 68 days after the birth of a pup, but due to delayed implantation of the blastocyst (which does not implant for 3 months), gestation periods last 9 months. Young are suckled for approximately 300 days before they are weaned (Seal Conservation Society).
Average birth mass: 3833.33 g.
Average gestation period: 236 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 1825 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1825 days.