Pups spend most of their time in groups or pods playing, sleeping, or residing near the water. They rarely swim into the deeper waters unless accompanied by their mothers. They typically first enter the water at about 3 to 4 weeks of age with other sea lions in a large group. They continue to nurse from their mother for about 6 to 12 months, until the following year when the mother gives birth to another pup. Even then mothers have been known to nurse both pups simultaneously.
Male pups mature later than female pups.
Male pups reach maturity at 6 years while females mature at 4 years. They both become full sized adults at around 8 years During development, mothers must be aware of group raids by invading males, who abduct their pups. These raids take place at any time of the day or night but is correlated with the number of females in oestrus, their location, and the tide level. This may be to obtain female pups soon in oestrus, to attract mothers away from their terrritory for mating purposes, or to signify strength and power. Some pups are killed by the males during these raids.