The breeding behavior is very territorial, with males holding aquatic and land territories. Males will often fight to maintain these territories. Females within each territory mate with the resident male. A. philippii are polygynous in their mating system.
Mating System: polygynous
Breeding in most fur seal and sea lion species occurs just after a female has given birth to a single pup from the preceding breeding season. In Juan Fernandez sea lions the peak pupping season is in late November and early December. Breeding occurs from November to January. Gestation is sligthtly less than one year.
Breeding interval: Juan Fernandez Fur Seals breed once yearly.
Breeding season: Mating occurs from November to December.
Average number of offspring: 1.
Average gestation period: 12 months.
Range weaning age: 7 to 10 months.
Range time to independence: 7 to 10 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous
Females give birth to a single pup and nurse on land. After a long initial post-natal suckling bout (averaging 11.3 days in length), females of A. philippii undergo long foraging trips (averaging 12.2 days in length), and this leads to some of the longest recorded intersuckling intervals for a mammal. Fat and energy content of milk is the highest of any member of the family Otariidae examined, allowing young to grow rapidly despite long periods of fasting.
Parental Investment: precocial ; female parental care