How big are the California sea lions?
The front flippers have all the major skeletal components of the forelimbs of land mammals, but are adapted for swimming. The "arm" bones are shortened, and the flipper digits are elongated by cartilaginous projections at the ends of the bones.
The California sea lion's front flippers are large and wing-like.
The first digit is larger than the others. It is reinforced by fibrous tissue along the posterior edge.
There are no claws or hairs on the front flippers.
Like land mammals, sea lions have five digits on their hind limbs. They are elongated by cartilaginous projections.
The middle three digits bear claws.
On land, a sea lion can curl its hind limbs under its rump, allowing it to support its weight and walk on all fours.
In the water, a sea lion extends its hind flippers and uses them to help steer.
Sea lions breed primarily on coastal islands, from the Channel Islands in southern California to Mexico, although a few pups have also been born on the Ani Nuevo and Farallon Islands in central California.
The California sea lion population is steadily increasing and is estimated to number around 257,000. They can be seen at many coastal locations in California, the most famous being PIER 39 in San Francisco.
California sea lions reach sexual maturity at about 3 years of age, while males reach sexual maturity at 5 years of age. Sea lions return to their breeding grounds in southern and central California each year, where females give birth to their pups in early summer. In fact, most California sea lions are born in the first two weeks of June each year.
Newborn California sea lions weigh between 13 and 20 pounds and stay with their mothers for about a year while they learn important nursing and survival skills, such as how to swim and find food on their own.
Mothers identify their pups in dense communities by smell and calls. In turn, the pups learn to recognize their mothers’ scent and calls. A few weeks after the females give birth, they are ready to mate again before the males migrate north to British Columbia.
California sea lions are highly social animals - groups often rest together in favorite roosts on land or float together on the ocean surface in what are called "rafts."
They are sometimes seen jumping out of the water, apparently to speed up their swimming. Sea lions have also been seen surfing storm waves.
As opportunistic feeders, California sea lions eat squid, octopus, and small shoaling fish such as herring, anchovies, and sardines. In turn, sea lions are preyed upon by orca whales and great white sharks, and they face a variety of other threats in the wild, including human activities, such as shooting and entanglement in ocean debris.
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