Zalophus californianus

Description and Fascinating Facts

California sea lions are seen on a whale watching boat tour with Eagle Wing Tours in Victoria, British Columbia, Canada on Vancouver Island.The 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. Males may reach 454 kg (1000 lbs), though the average is 390 kg (858 lbs) and 2.1 m (8 ft) in length. Females grow to 110 kg (200 lbs.) and up to 1.8 m (6 ft) 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 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 trained seals in zoos and aquaria are usually California sea lions. The sea lion family is large, ranging from around 150 kg (330 lbs) to over 1500 kg (3300 lbs), and males tend to be much larger than females (called sexual dimorphism). Their bodies are slender and elongate. Small, cartilaginous, external ears are present. All otariids have fur. In the sea lions, relatively coarse hairs predominate, while in the fur seals, dense underfur is also present. Colors are generally shades of brown, without stripes or other contrasting markings. The fore flippers of otariids are long and paddle-like, more than a quarter of the length of the body. The surfaces of the fore flippers 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 highly social, forming large herds 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. Females arrive and segregate into harems of 3–40 individuals, depending on the size and strength of the male. Soon after they arrive, females 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 insures that the young will be born in a year, when the breeding herds again form.

World Range and 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 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.

Feeding Behavior

California sea lions are opportunistic feeders diving up to depths of 135 m (450 ft) and eat such things as squid, octopus, herring, rockfish, mackerel, and salmon. In turn, sea lions are preyed upon by orca (killer whales) and great white sharks.

Reproduction

An alpha male taking in the sun. California sea lions are often seen on whale watching tours with Eagle Wing Tours.

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.

Warnings and Comments

California sea lions are very social animals, and groups often rest closely packed together at favoured haul-out sites on land, or float together on the ocean’s surface in “rafts”. They are sometimes seen porpoising through the water at 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 gill nets and other marine debris. However, their population is growing steadily, and California sea lions can be seen in many coastal spots such as Seal Rocks or PIER 39 in San Francisco, and at BC’s very own Race Rocks Ecological Reserve.