Both seals and sea lions, together with the walrus, are pinnipeds, which means “fin-footed” in Latin. They are mammals, which means that they have live young, produce milk, have hair (or fur) on their bodies, and breathe air.
While seals and sea lions have much in common, there are many notable differences:
- The average weight of a male harbor seal is about 300 pounds and they are about 6 feet long, while a male California sea lion weighs on average 700-800 pounds and is 7-8 feet long.
- The average weight of a female harbor seal is about 200 pounds and they are about 5 feet long, while a female sea lion weighs on average 225 pounds and is 6 feet long.
- Harbor seals have short, hairy, webbed front flippers with claws, whereas sea lions have long, hairless, clawless and mostly skin-covered, fore flippers.
- Seals lack external ears — they have a tiny ear hole on each side of their head — whereas sea lions have small flaps for outer ears.
- Seals have spotted coats in a variety of shades from white or silver-gray to black or dark brown, while sea lions are brown — their color ranges from chocolate brown in males to a lighter, golden brown in females.
- In the La Jolla area, the harbor seals live at Casa Beach, while the sea lions live about a half mile north at the Cove.
- When swimming, seals use their back flippers for power and their front flippers for steering. Sea lions are the opposite, using their foreflippers for power and their back flippers for steering.
- The hind flippers of seals angle backward and don’t rotate. This makes them fast and graceful in the water; however they can only move on land by wiggling awkwardly on their belly. Sea lions, on the other hand, are able to “walk” on land by rotating their hind flippers forward and underneath their big bodies.
- Seals are less social than their gregarious sea-lion cousins. Seals never touch each other, with the exception of the time when a mom bonds with her newborn pup; whereas sea lions are happy to pile on top of each other when hauling out on the rocks or sand.
- Seals are quiet, vocalizing only via soft grunts, while sea lions are quite noisy – they bark a lot!