The Influence of El Niño on Female Attendance Patterns in the California Sea Lion

As is typical of otariids, California sea lion (Zalophus californianus) females alternate foraging trips to sea with nursing bouts on land (hereafter referred to as “attendance patterns”) during the breeding season. Sea lion pups are entirely nutritionally dependent upon their mothers throughout the first several months of life (Ono et al. 1987). Also, a proportion of pups remain with their mothers into the next breeding season and continue to nurse as juveniles (Francis and Heath, Chap. 21, this Vol.). Alterations in attendance patterns may therefore affect the health and survival of both pups and older suckling juveniles.