These pinnipeds may spend several days to several weeks at sea foraging.During this time they dive almost continuously, taking brief surface rests.Pups are dark brown to black when born, fading to light brown within a few weeks.At approximately four to five months of age, pups molt to a light gray pelage, darkening to a dark chocolate that fades to light tan.
Pups are weaned abruptly and abandoned by their mothers usually when six months old. When hauled out they rest close to and often on top of each other.
Their hind flippers, used as rudders for steering, are much shorter and have fleshy tips and short narrow claws at the end of the digits. Mature males have a prominent protruding forehead with a large bump of bone called the sagittal crest. Unlike other sea lions, California sea lions do not have a lion-like mane.
Adult males are mainly a dark chocolate-brown color, except for light tan areas on the face. Most males do not fade to a lighter color after molting.
These sea lions have a long, straight, and narrow snout and distinct, small, external ears.
Long paddle-like fore flippers that end in tiny claws with hair on the upper surface extending past the wrist are used for propulsion through the water.