Guadalupe fur seals have a polygynous breeding system, which involves a male seal with a territory (a bull) defending both his terriory and the females in his harem. The harem numbers between 4 to 12 females, each of which typically have one pup that they nurse.
Mating System: polygynous
Male Guadalupe fur seals are territorial, like other fur seals. They defend harems that number an average of 6.2 breeding females for each territorial bull. Males will defend their territory for 35 to 122 days. Unlike most other seal species, the males of A. townsendi occasionally observe their harems from the water. Female Guadalupe fur seals mate 7-10 days after giving birth to a pup conceived the previous year (post-partum estrus). Females lactate for an average of 9-11 months; how this related to the actual length of time before weaning is unclear.
(Whitaker, 1997; Wickens & York, 1997)
Breeding season: 15 June - 22 July
Average number of offspring: 1.
Average gestation period: approximately 12 months.
Average weaning age: most likely 11 months.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
Parental Investment: female parental care