California Sea Lion

Sea lion or seal? How to tell

California sea lions have small external ear flaps, long front flippers they use to swim, and hind flippers they can rotate forward to walk on land. Harbor seals, the other common animal on our coast, have no ear flaps, swim with their hind flippers and wriggle on their bellies ashore. If it barks and climbs onto a buoy, it is a sea lion.

Adult males are big, up to about 8 feet and 800 pounds, with a raised forehead crest; females are around 6 feet and 220 pounds. They live 20 to 30 years.

Speed, diving and diet

Sea lions are among the fastest swimmers of any seal or sea lion, with bursts near 25 miles per hour, and they routinely dive a few hundred feet, occasionally much deeper, for a few minutes at a time. They eat what the ocean offers: sardines, anchovies, mackerel, squid, hake and rockfish, mostly at night.

Where they breed

The big rookeries are on islands: San Miguel and San Nicolas in California's Channel Islands, where tens of thousands of pups are born each June, and the Coronado Islands and Baja coast in Mexico. Males fast for weeks defending beach territories; females give birth, mate again within days, and then alternate feeding trips at sea with nursing on the beach for close to a year.

A recovery that is still being tested

Hunted and culled into the early 1900s, California sea lions recovered after the Marine Mammal Protection Act of 1972 and now number in the hundreds of thousands, close to what the coast can support. That success has two sides: more animals on docks and beaches, and more animals exposed to new pressures.

The pressures are warm water, which pushes sardines and anchovies away from the rookeries and leaves pups starving, as in the strandings of 2013 to 2016; domoic acid from toxic algal blooms, which causes seizures and strands adults in bad years; entanglement in fishing line and packing straps; and gunshot wounds from conflicts over fish. Rescue centers along the coast exist mostly for this animal.