Sea lions in the family Otariidae, including Galapagos sea lions, practice polygamy. Little is otherwise known regarding the mating systems of this species.
Mating System: polygynous
Galapagos sea lions have a long breeding season from May to January, as witnessed by the great size variation of Galapagos sea lions within the Galapagos Archipelago. Gestation lasts 11 months, and single pup is born per female during each breeding interval. Male and female pups weigh about 6 kg when born, and they are weaned at 11 to 12 months of age. Galapagos sea lion pups are partially independent between 12 and 24 months, while still returning to nurse from time to time (Aurioles and Trillmich, 2008; Halpin et al., 2009; Orr, 1967). The age of sexual maturity for both male and female Galapagos sea lions is between 4 and 5 years of age (Aurioles and Trillmich, 2008).
Breeding interval: Galapagos sea lions breed once yearly.
Breeding season: Galapagos sea lions breed between May and January.
Average number of offspring: 1.
Average gestation period: 11 months.
Average birth mass: 6 kg.
Average weaning age: 11 to 12 months.
Average time to independence: 12 to 24 months.
Average age at sexual or reproductive maturity (female): 4 to 5 years.
Average age at sexual or reproductive maturity (male): 4 to 5 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
Mother Galapagos sea lions have a close bond with their pups. Mothers attend to their pups continuously for 6 to 7 days after birth, after which they feed in the sea, returning at night to continue feeding their young. Mother and pups recognize each other by their unique scent and vocal calls (Halpin et al., 2009). Female sea lions nurse only one pup at a time, until they give birth to the next pup. Some females allow both her yearling and pup to nurse simultaneously. If the female does not bare another pup, then the first can nurse for up to three years (Trillmich, 1981).
Parental Investment: female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
- Aurioles, D., F. Trillmich. 2008. "Zalophus wollebaeki." (On-line). IUCN Red List of Threatened Species.. Accessed April 26, 2009 at http://188.8.131.52/search?q=cache:HPbRfWi1D4wJ:www.iucnredlist.org/details/41668+Zalophus+wollebaeki+longevity&cd=1&hl=en&ct=clnk&gl=us.
- Halpin, A., P. Crowder, B. Best, E. Fujioka. 2009. "Mapping marine mammals, birds and turtles." (On-line). OBIS SEAMAP. Accessed February 08, 2009 at http://seamap.env.duke.edu/species/tsn/622014.
- Orr, R. 1967. The Galapagos Sea Lion. Journal of Mammalogy, Vol 48: 62-69. Accessed February 02, 2009 at http://www.jstor.org/stable/1378170?&Search=yes&term=lion&term=sea&term=Galapagos&list=hide&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3DGalapagos%2Bsea%2Blion%2B%26x%3D8%26y%3D15%26wc%3Don&item=6&ttl=400&returnArticleService=showArticle.
- Trillmich, F. 1981. Mutual Mother-Pup Recognition in Galápagos Fur Seals and Sea Lions: Cues Used and Functional Significance. Behaviour, 78: 21-42. Accessed February 08, 2009 at http://www.jstor.org/stable/info/4534129?seq=1.