California Sea Lion Fact File
Wild 17 years
Captive 31 years
California sea lions are found along the west coast of North America where they are a common sight around piers and marinas.
These creatures are highly social with large numbers gathering at sites where they rest together. When they go out to hunt they will split in to small groups which target fish, octopus and squid.
Due to their high level of intelligence these animals are regularly trained to perform in captive situations. They have also been used in military operations.
They are threatened by human interference, entanglement in fishing gear and toxins from algal blooms.
Learn more about them by reading on below.
Male California sea lions are a chocolate brown in color while females are a golden brown color. After the molt females may appear to be a light grey or silver color. Most sea lions appear dark brown or black when wet. The chest is lighter in color.
Their front flippers are large allowing them to walk effectively on land. This flipper has bones inside that are same as those in a humans arm. The bones are shorter and the fingers are extended with cartilage. The back flippers are formed with 5 digits like the foot of a human. On the middle three toes are nails.
A small flattened tail sits between the two hind flippers. Male California sea lions have a raised portion of their forehead known as a sagittal crest. This can measure up to 4cm (1.5in) tall. Females have a smooth forehead.
As a seal they have visible ear flap on either side of the head.
Males are larger typically measuring 2.4m (7.9ft) long. They can weigh up to 350kg (770lb). Females typically reach 1.8m (5.9ft) and weigh up to 100kg (220lb).
California sea lions are carnivores. They feed on fish, squid, octopus and the occasional clam.
They have a few interesting hunting techniques. One is to follow dolphins and catch some of the fish which they are chasing. Another is to co-operate with dolphins, porpoises and seabirds to hunt a large school of fish.
California sea lions live along the coast of the Americas from British Columbia to Mexico. This includes a number of offshore islands. A colony used to live on the coast of a few Japanese islands but it is now believed this is extinct.
These animals are occasional vagrants to Costa Rica; El Salvador; Guatemala and Honduras.
The sea lions on the Galapagos islands used to be thought of as a subspecies of California sea lions but are now seen as their own species.
Sandy beaches and rocky areas are the most common homes of California sea lions. Most of the time they are found in the waters of the Pacific Ocean.
Increasingly they are making their way into freshwater rivers.
They will rest on man-made structures such as jetties, piers, buoys and oil platforms where available.
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Between May and August the sea lions gather at a rookery where they will breed.
Here males establish a territory which they defend for as long as possible. They do not eat during this period living off the blubber. A larger male will be more successful as he can store more blubber. It is very hot during the breeding season so part of the territory always has water for the male to sit in with some even being completely in the water.
Females form a group of 2-20 individuals and begin to move through the territories of the males. Males do not work too hard to keep females in their territory and females do not like males to be too energetic or aggressive.
There is a delay between mating and implantation of three months. Following this gestation takes 8 months. They give birth in June or July. A single pup is born at the end of this period.
For the first week of their life the mother stays with the pup to nurse it. After this she heads out to sea for up to three days before returning to spend 2-3 days nursing the pup. While they are left on the shore pups form nurseries where they can socialize and play. The mother and pup can find each other on the beach due to their distinct calls.
Weaning age varies greatly in California sea lions. Some wean at 6 months while for others it takes a year. There is believed to be a number of reasons for this. These include food availability, the mother’s age, the sex of the pup and if a new pup is born. Females spend more time with the mother before striking out on their own than males do.
Sexual maturity occurs between 4 and 5 years of age though most males cannot hold a territory until they are much older.
Some instances of pups being fostered by other sea lions after they are abandoned have been recorded.
California sea lions are highly social. They gather in large groups to rest and will tolerate others lying on them or close to them. In the water they create a raft which is a mass of sea lions close together. When it is time to go hunting they form small groups unless they are going after a large number of fish.
When diving they can reach depths of 274m (899ft) and swim at between 15-20mph (24-32 km/h).
Juvenile and non-breeding California sea lions have been seen engaging in play activities such as surfing, chasing each other, pushing and shoving each other off rocks and mock fights. On occasion adults are seen participating.
The California sea lion is one of the most vocal mammals. They make barks, growls and grunts.
Predators and Threats
Humans affect the population of California sea lions through entanglement in fishing gear, toxins from algal blooms and injuries caused by humans such as gunshots.
Populations of this species have increased since 1975 when they were offered protection under the Marine Mammal Protection Act.
California sea lions are the ones most commonly seen performing at zoos and aquariums. They are highly intelligent and have been taught to understand a simple version of sign language.
Groups of California sea lions have been trained for use in military operations and are still part of active duty today.
Aurioles-Gamboa, D. & Hernández-Camacho, J. 2015. Zalophus californianus. The IUCN Red List of Threatened Species 2015: e.T41666A45230310. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T41666A45230310.en. Downloaded on 11 May 2020.
NOAA. 2021. California Sea Lion. [online] Available at: <https://www.fisheries.noaa.gov/species/california-sea-lion> [Accessed 19 June 2021].
Marinemammalcenter.org. 2021. California Sea Lion | The Marine Mammal Center. [online] Available at: <https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/pinnipeds/california-sea-lion> [Accessed 19 June 2021].