California Sea Lion (Zalophus californianus)
- known for their dog-like barking
- found from southern BC to Mexico
- breed mainly in California southwards
- females generally stay near the breeding sites all year
- have an active and comical disposition
- males spread out after breeding season and about 3,000 animals go as far north as southern Vancouver Island during fall and winter months
- dark chocolate brown colour, males have a prominent bump on their forehead called a sagittal crest
- males are 2–2.5 m (6–8 ft.) long and weigh approx. 400 kg (900 lb.), females smaller at 1.8 m (6 ft.) and 110 kg (200 lb.)
- feed mainly on small schooling fish, also salmon, dogfish, skate, squid
California sea lions are well known for their intelligence, playfulness, and dog-like barking. Their colour tends toward chocolate brown, although females are often a lighter golden brown. They have a dog-like face and at around five years old 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 too.
These members of the Otariidae or “walking seal” family have external ear flaps and large flippers that they use to walk with on land. The foreflippers are long and paddle-like, more than a quarter of the length of the body. The surfaces of the foreflippers are naked and leathery, and claws are present but small. The hind flippers are also large. They differ from those of true seals (Phocids) in that they can be rotated under the animal when it is on land, partially supporting the body and walking with a swaying motion. Otariids also have a small but distinct tail.
Otariids tend to be very social, forming large herds at “rookeries” during the breeding season. Within these herds, individual males maintain harems. Males arrive on the breeding grounds before females and set up territories, which they defend aggressively. Soon after the females arrive, they give birth to pups from the previous year’s breeding season, and within a few days enter estrous. Mating takes place on land. A period of delayed implantation ensures that the next pup will be born in a year’s time, when the herds again gather at the rookeries.
Range and habitat
California sea lions are found from Vancouver Island BC to the southern tip of Baja California in Mexico. They breed mainly on offshore islands 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. The current population is estimated at approximately 100,000. An estimated 3,000 spend the winter in BC waters.
California sea lions are opportunistic feeders diving up to depths of 135 m (450 ft) looking for squid, octopus, herring, rockfish, mackerel, and salmon. In turn, sea lions are preyed upon by killer whales and great white sharks.
One pup per female is born in June or July and weighs 6–9 kg (19 lbs). They nurse for at least 5–6 months and sometimes for over a year. Mothers recognize pups on crowded rookeries through smell, sight and their 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.
California sea lions are very social animals and often rest closely packed together at favoured haul-out sites on land, or float together on the ocean’s surface in “rafts.” They’re sometimes seen porpoising through the water at speeds of up to 45 kph (15–20 mph). Sea lions have also been seen “surfing” breaking waves. Sea lions have frequently been found illegally shot and also caught in drift or gillnets and other marine debris. California sea lions can be seen in many coastal spots such as Seal Rock, Oregon, Pier 39 in San Francisco, and at BC’s Race Rocks Ecological Reserve.