The California sea lion is found from southern Mexico to southwestern Canada.  The breeding areas of the California sea lion are on islands located in southern California in the U.S. and in western Baja California and the Gulf of California in Mexico.  Males establish breeding territories May through July on both land and in the water. Females come ashore in May and June where they give birth to a single pup 4 to 5 days after arrival.  Females nurse pups for about a week before going on their first feeding trip.  They alternate feeding trips with nursing bouts until the pup is weaned between at 4 and 10 months of age.  In normal years, adult and juvenile males migrate as far north as British Columbia, Canada while females and pups remain in southern California waters in the non-breeding season.  In warm water (El Niño) years, some females are found as far north as Washington and Oregon, presumably following prey.  Adult males can be as large as 2.4 m and 390 kg; adult females average 2m and 110 kg.