California sea lions are furry marine mammals that live along the southern coast of Alaska to Central Mexico. They can be easily distinguished from other seals in their range because they have protruding ears. Sea lions are sexually dimorphic, meaning that males and females do not look the same. Males are much larger than females, and typically weigh around 770 lbs, while females only reach a weight of around 200 lbs.
The sea lions feed primarily on fish, squid and shellfish. They are highly intelligent and have been observed cooperating with dolphins when hunting large schools of fish. They are so smart that the U.S. Navy trains them to protect ships from enemy divers by swimming behind the unsuspecting divers and attaching a clamp and rope to their legs.
During breeding, males establish a territory on a beach and compete with other males through barking and aggressive behavior to protect their space. A single male will mate with many females, but females typically choose their mate by selecting a male based on his temperament and his breeding territory. A male sea lion typically can hold his territory for about a month, during which time he will fast, surviving on his thick layer of stored blubber. After a month, the male will have to return to the sea to find prey to replenish his blubber layer.
Sea lions are abundant along the North American Pacific coast, and are not considered to be endangered. They are an important food source for large sharks and transient mammal-eating killer whales. We were extremely lucky to encounter a playful group of sea lion pups while diving in Espíritu Santo National Park near La Paz, Mexico. Read more in our post, Sea Lions and Whale Sharks: Scuba Diving in La Paz, Mexico.