California Sea Lion
Zalophus californianus
Conservation: There are roughly 110,000 California sea lions living in the wild. The California Sea Lion is protected by Marine Mammals Protection Act, so it is illegal to kill or capture any species of sea lion in the United States and Mexico except by a special permit. Eskimos and Native Americans are allowed to hunt them for food, clothing, and traditional arts.
Behavior: The California Sea Lion is an excellent underwater swimmer. This sea lion uses underwater sonar for navigation. They come ashore to breed and to rest. The males of this species are very territorial. They set up and defend their territories when the females arrive for breeding. Stereotyped boundary maintenance displays include behaviours such as oblique stares, head shaking, barking, and lunges towards the opponent. These displays rarely result in harm to either animal. The young nurse until the next pup is born, but with time the frequency and duration of nursing periods shortens. Females will wail to their young who respond with calf-like bleats. Females will also bark and growl in aggressive interaction with other females.
Breeding: California sea lions are polygynous (one male and several females), with males establishing territories along the coasts of Southern California and Baja California. The places are often called rookeries and become very noisy because the males are always barking to defend their territory. Mating occurs during May to June, and after a gestation period of about 12 months, a pup is born in July or August. Pups may be born either on land or in water, with open eyes and the ability to vocalize. Several days after pups are born the mother will leave them in the rookery in search of food. When she returns she will sound a loud trumpeting vocalization, which elicits a bleating response from her pup(s). This calling continues until the pups are found. The identification is complete when the mother smells her pups to make sure they belong to her.
Threats to Survival: California sea lions are currently listed as threatened, however, outside of sharks and killer whales, sea lions do not have many natural threats. They are susceptible to a viral disease known as sea lion pox, believed to be transmitted by mosquitoes into open wounds. It can cause paralysis, which prevents the animal from feeding and ultimately leads to death. Evidence suggests, however, that sea lions are gradually building up a resistance to this disease. Sea lions are also known to have such diseases as pneumonia, caused by a parasitic lungworm, and a bacterial infection called leptospirosis, which affects their livers and kidneys. Sea lions are seen as a competitor with the fishing industry, however they cannot be commercially hunted so this has not risen to a true threat to the survival of the species. A major threat to their survival is ocean pollution, in the form of both oil spills and trash. The trash is often ingested, causing intestinal blockages that can be fatal. Discarded plastic products and abandoned fishing nets are additional sources of danger that often strangle, choke and/or poison these animals.
Zoo Programs: Currently there are no breeding programs for California sea lions. Due to their intelligence and ability to learn and interact with dedicated trainers, sea lions are frequently used for educational programs, such as Como Zoo's Sparky the Sea Lion Show.
Sea lion C404 is seen in the fish ladder at Bonneville Dam Tuesday, March 21, 2006, in Cascade Locks, Ore. Numerous sea lions head for the dam each spring, but C404 is in a class alone. Extra gates, firecrackers, rockets, and rubber bullets so far haven't kept the whiskered rascal out. They will have to think up new strategies, but can't kill C404 because sea lions are protected under the 1972 Marine Mammal Protection Act. (AP Photo/Rick Bowmer) AP - Mar 31 9:24 PM
Sea lion C404 is seen in the fish ladder at Bonneville Dam Tuesday, March 21, 2006, in Cascade Locks, Ore. Numerous sea lions head for the dam each spring, but C404 is in a class alone. Extra gates, firecrackers, rockets, and rubber bullets so far haven't kept the whiskered rascal out. They will have to think up new strategies, but they can't kill C404 because sea lions are protected under the 1972 Marine Mammal Protection Act. (AP Photo/Rick Bowmer) AP - Mar 31 9:23 PM
Sea lion C404 is seen in the fish ladder at Bonneville Dam Tuesday, March 21, 2006, in Cascade Locks, Ore. Numerous sea lions head for the dam each spring, but C404 is in a class alone. Extra gates, firecrackers, rockets, and rubber bullets so far haven't kept the whiskered rascal out. They will have to think up new strategies, bu can't kill C-four-oh-four because sea lions are protected under the 1972 Marine Mammal Protection Act. (AP Photo/Rick Bowmer) AP - Mar 31 9:24 PM
Sea lion C404 is seen in the fish ladder at Bonneville Dam Tuesday, March 21, 2006, in Cascade Locks, Ore. Numerous sea lions head for the dam each spring, but C404 is in a class alone. Extra gates, firecrackers, rockets, and rubber bullets so far haven't kept the whiskered rascal out. They will have to think up new strategies, but can't kill C404 because sea lions are protected under the 1972 Marine Mammal Protection Act. (AP Photo/Rick Bowmer) AP - Mar 31 9:24 PMSea lion C404 is seen in the fish ladder at Bonneville Dam, March 21, 2006, in Cascade Locks, Ore. Numerous sea lions head for the dam each spring, but C404 is in a class alone. Extra gates, firecrackers, rockets, and rubber bullets so far haven't kept the whiskered rascal out. They will have to think up new strategies, but can't kill C404 because sea lions are protected under the 1972 Marine Mammal Protection Act. (AP Photo/Rick Bowmer)
AP - Mar 31 4:09 PM