Reproductive Behavior and Life History
Reproductively mature male sea lions aggregate in May on traditional, well-defined reproductive rookeries, usually on beaches on isolated islands. The larger, older males establish and defend distinct territories on the rookery. A week or so later, adult females arrive, accompanied occasionally by sexually immature offspring, and form fluid aggregations throughout the rookery. Like all other otariids, Steller sea lions are polygynous. However, unlike some other species, they do not coerce individual females into harems but control spatial territories among which females freely move about. Steller sea lions have used three types of territories; aquatic, semiaquatic and terrestrial. Males with semiaquatic territories have the most success in defending them. The boundaries of territories are defined by natural features, such as rocks, faults or ridges in rocks. Territories can remain stable for 60 days.
Pregnant females give birth soon after arriving on a rookery, and copulation generally occurs one to two weeks after giving birth, but the fertilized egg does not become implanted in the uterus until the fall. Twins are rare. After a week or so of nursing without leaving the rookery, females begin to take progressively longer and more frequent foraging trips, leaving their pups behind, until at some point in late summer the mother and pup both leave the rookery. Reproductive males fast throughout the reproductive season, often without entering the water once from mid-May until August, at which point the structure of the reproductive rookeries begins to fall apart and most animals leave for the open seas and disperse throughout their range.
The age at weaning is highly variable; pups may remain with their mothers for as long as four years. Incidents of mothers feeding daughters who are simultaneously feeding their own newborn pups have been documented, an extremely rare occurrence among mammals.
Read more about this topic: Steller Sea Lion
Famous quotes containing the words reproductive, behavior, life and/or history:
“The blind conviction that we have to do something about other people’s reproductive behaviour, and that we may have to do it whether they like it or not, derives from the assumption that the world belongs to us, who have so expertly depleted its resources, rather than to them, who have not.”
—Germaine Greer (b. 1939)
“As long as male behavior is taken to be the norm, there can be no serious questioning of male traits and behavior. A norm is by definition a standard for judging; it is not itself subject to judgment.”
—Myriam Miedzian, U.S. author. Boys Will Be Boys, ch. 1 (1991)
“... aside from the financial aspect, [there] is more: the life of my work. I feel that is all I came into the world for, and have failed dismally if it is not a success.”
—Mary E. Wilkins Freeman (1852–1930)
“I am ashamed to see what a shallow village tale our so-called History is. How many times must we say Rome, and Paris, and Constantinople! What does Rome know of rat and lizard? What are Olympiads and Consulates to these neighboring systems of being? Nay, what food or experience or succor have they for the Esquimaux seal-hunter, or the Kanaka in his canoe, for the fisherman, the stevedore, the porter?”
—Ralph Waldo Emerson (1803–1882)