California sea lions belong to the genus Zalophus californianus. They are a common sight at aquatic zoos, marine parks, and circuses. Their adaptability to human presence and environs have made them a popular choice for US Navy for military operations.
A healthy male California sea lion attains a weight of approximately 300 kg and a length of around 8 ft. The females exhibit a weight of about 90 kg and a length not more than 6.5 feet. The mammal has a pointed muzzle, giving it a very dog-like appearance. On reaching sexual maturity, the males develop a large bony crest on the top of their heads. It is this very features that earns the animal the generic name Zalophus. 'Za' stands for emphatic, while 'lophus' relates to the forehead. Literally translated, Zalophus californianus means 'Californian big-head'.
Like the male South American Steller sea lion, a male lion also has a mane. However, it is not as well-developed. The males and pups have a darker purplish skin color than the females. The average lifespan is approximately 18 years. They are able to stay underwater for periods up to 15 minutes or more, by sealing their noses shut. Other than the waters around California, this sea lion is also sighted near coasts and bays of Oregon, British Columbia, Washington, Mexico and the islands of Channel and San Nicolas.
These marine mammals breed on the beaches, leaving the sandy coves to venture not more than 10 miles into the sea. They inhabit the water's edge, coastal slopes, marinas, wharves and even navigational buoys. They have come to recognize man-made environs as safety zones from their natural predators, sharks and orcas. These sea lions are also seen in freshwater biomes. They feast on a variety of seafood, especially salmon and squid. They also feed on clams, hake, herring, Pacific whiting, lamprey, anchovies, and other schooling fish that thrive in the continental shelves and sea mounts.
Depending on the amount of food available, they may choose to eat alone or in a group. This mammal exhibits unique social behavior, as it co-exists and feeds alongside dolphins, seabirds, and even sharks, who simultaneously feed on large schools of migratory fish. They mainly breed between May and June. The males are known to fast during the courting period, using their blubber as an energy reserve. Size plays an important role in a fight over a female.
Male fights involve violent, ritualized roaring, bluff plunges, and head-shaking. After a gestation period of a year, females give birth to pups either on land or in water. The new-born pups instantly vocalize with the mother. They nurse for up to six months on milk that does not contain lactose. Within two months, the pups swim and hunt alongside their mothers. A size dominant hierarchy exists in this sea lion's social arena. These marine mammals are highly intelligent and trainable. At marine parks, they display skills involved in throwing and catching balls, running up ladders, and even singing! California sea lions are now protected under the clauses of the US Marine Mammal Protection Act.