California Sea Lion Backgrounder
Sea Lion Sound opens June 30, 2012 at the Saint Louis Zoo.
California Sea Lions
Range and Habitat
The main population of California sea lions is found along the west coast in the Pacific Ocean, ranging from Baja, California, south to Mexico and north into British Columbia, Canada. Their habitat is ocean waters, and sandy or rocky coastlines.
What’s a Pinniped?
Sea lions, seals and walruses are marine mammals belonging to an order, or group, called pinnipeds, which means “fin-footed” or “wing-footed.” One way to tell the difference between seals and sea lions is to look at their ears. Harbor seals and other “true” seals do not have external ear flaps. Sea lions, fur seals and walruses have visible, external ear flaps.
Big on Looks
Male California sea lions, called bulls, can reach 6.5 to 8 feet in length and weigh 500 to 800 pounds. Females, or cows, are smaller, ranging from 5 to 6.5 feet in length and weighing 150 to 225 pounds. Their color ranges from chocolate brown in males to a lighter, golden brown in females.
Sea lions have a thick layer of fat, called blubber, which helps with buoyancy and swimming, serves as an energy reserve, and helps to regulate their body temperature.
Sea lions have the same bone structure in their fore flippers as humans have in hands, though theirs are modified for swimming. They also have five “fingers” in their hind flippers – they even have three toenails. Sea lions can rotate their hind flippers under their body, allowing them to stand on all four limbs. Using both their fore flippers and hind flippers, they are able to walk on land.
The playful, curious California sea lions are very social animals. In the wild, they typically live in groups, or “harems,” that include a bull and 10 to 15 cows. During their summer-long breeding season, they collect by the thousands on isolated coastlines and islands. Males patrol territories and bark almost continuously during the breeding season.
Stellar Swimmers & Deep Sea Divers
Sea lions are great swimmers, reaching up to 15 miles per hour. They are sometimes seen "porpoising," or jumping out of the water, presumably to speed up their swimming. A sea lion’s sleek body is built for diving deep into the ocean in search of food. They can dive to depths of up to 1,000 feet – that’s the length of almost three football fields. When a sea lion dives, its inner ears and nostrils close. Tears continually wash over their eyes to protect them.
Sea lions can remain under water for up to 20 minutes at a time. Unlike dolphins (and humans), sea lions actually exhale before a dive. They can stay underwater for long periods because they have a high tolerance for carbon dioxide.
Are You My Mother?
Mothers recognize pups on crowded rookeries through smell and vocalizations. A sea lion pup can pick its mother out from hundreds of sea lions just by the sound she makes. When a mother returns to the harem after finding food, she makes a loud trumpeting sound that prompts a bleating response from her pup. This exchange continues until mother and pup find each other.
California sea lions can eat over 30 pounds of food per day. They are opportunistic eaters, feeding on squid, octopus, herring, rockfish, mackerel, and small sharks. In turn, sea lions are preyed upon by orcas (killer whales) and great white sharks.
A sea lion’s whiskers contain nerves that make them sensitive to vibrations. They use their whiskers to find their way around and detect vibrations from prey in the water. A sea lion can balance a ball by feeling the ball with its whiskers and adjusting its head and body to keep it stable.
Sea lions, like many marine mammals, can see well both above and below water. Unlike humans, they don’t see in color. Instead they see in black and white but can pick up tones of green and blue. This helps them detect movement in their aquatic environment.
Sustainable Seafood and Ocean Conservation
All marine mammals are protected by the federally regulated Marine Mammal Protection Act. Though California sea lions are listed as “common” and not currently endangered in the wild, other marine species are.
Ocean animals are often accidentally caught during commercial fishing for other fish. It’s important that consumers purchase seafood from suppliers that farm or fish in ways that will ensure the long-term health of the world’s oceans, rivers and lakes. Visitors can pick up a Midwest Seafood Watch Pocket Guide at the Zoo for a list of recommended seafood choices (and those that are not recommended). A card can also be downloaded at www.stlzoo.org.
Here are a few ways that humans can make a difference for marine mammals and other ocean inhabitants:
- Dispose of waste properly, and avoid using plastic bags – it can all end up in the ocean.
- Conserve water and energy use.
- Recycle paper, plastic, aluminum and glass.
- Reduce the amount of chemicals used on lawns and gardens.
- Eat seafood products that are sustainable.
- Reduce, reuse and recycle. Pass it on!