Pinnipedia, from the Latin pinna (fin) and ped- (foot), is a taxonomic clade of semiaquatic mammals that includes seals, sea lions and walruses. Pinnipeds are close relatives of modern bears, and part of the order Carnivora. There are four species of pinnepeds in the northeast Pacific; two seals and two sea lions.

Although very similar in appearance, seals and sea lions differ on a few key features. Sea lions have external earflaps and long, furless front flippers. They can raise their heads and shoulders and rotate their hind flippers underneath their bodies, allowing them to walk and gallop on land. Seals have no external earflaps and short, fur-covered front flippers. They cannot raise their heads and shoulders very well, and are...