CALIFORNIA SEA LION
Zalophus californianus
meaning of Latin name: with crest and of California

DESCRIPTION: California sea lions are known for their intelligence, playfulness, and noisy barking. Their color ranges from chocolate brown in males to a lighter, golden brown in females. Males may reach 1,000 lbs. (more often 850 lbs., or 390 kg) and seven feet (2.1 m) in length. Females grow to 220 lbs. (110 kg) and up to six feet (1.8 m) in length. They have a "dog-like" face, and at around five years of age, males develop a bony bump on top of their skull called a sagittal crest. The top of a male's head often gets lighter with age. These members of the otariid or walking seal family have external ear flaps and large flippers that they use to "walk" on land. The trained "seals" in zoos and aquariums are usually California sea lions.

RANGE/HABITAT: California sea lions are found from Vancouver Island, British Columbia to the southern tip of Baja California in Mexico. They breed mainly on offshore islands, ranging from southern California's Channel Islands south to Mexico, although a few pups have been born on Año Nuevo and the Farallon Islands in central California. There is a distinct population of California sea lions at the Galapagos Islands. A third population in the Sea of Japan became extinct, probably during World War II.

BEHAVIOR: California sea lions are very social animals, and groups often rest closely packed together at favored haul-out sites on land, or float together on the ocean's surface in "rafts." They are sometimes seen porpoising, or jumping out of the water, presumably to speed up their swimming. Sea lions have also been seen "surfing" breaking waves. California sea lions are opportunistic eaters, feeding on squid, octopus, herring, rockfish, mackerel, and small sharks. In turn, sea lions are preyed upon by Orcas (killer whales) and great white sharks.

MATING AND BREEDING: Most pups are born in June or July and weigh 13-20 lbs. (6-9 kg). They nurse for at least five to six months and sometimes over a year. Mothers recognize pups on crowded rookeries through smell, sight, and vocalizations. Pups also learn to recognize the vocalizations of their mothers. Breeding takes place a few weeks after birth. Males patrol territories and bark almost continuously during the breeding season.

STATUS: Their population is growing steadily, and California sea lions can be seen in many coastal spots such as Seal Rock or PIER 39 in San Francisco. The current population is approximately 200,000.

AT THE MARINE MAMMAL CENTER: Each year, many California sea lions are treated at The Marine Mammal Center. Sea lions are known to have such diseases as pneumonia, caused by a parasitic lungworm, and a bacterial infection called leptospirosis, which affects their livers and kidneys. In 1998 and again in 2000, large numbers of sea lions were treated for domoic acid poisoning, a condition caused by harmful algal blooms which causes the animals to have seizures. Other problems for California sea lions involve humans. Sea lions have been found illegally shot and also caught in drift or gill nets and other marine debris. Between January 1986 and September 1998, 7.5% of all the seals and sea lions treated by The Marine Mammal Center had human-related injuries. The majority of these incidents involved California sea lions.

May be reprinted for scientific and educational purposes

Revised 2/02

Learn more about the following:

Harbor Seal
Northern Elephant Seal
Steller Sea Lion
Northern Fur Seal
Guadalupe Fur Seal