Harbor seals inhabit shallow areas of estuaries, rivers, and places where sandbars can be found during low tide. They are found in temperate, sub-arctic and arctic waters of the North Atlantic and North Pacific oceans. Harbor seals eat squid, crustaceans, and various fish including salmon, herring, and also flounder. Adult males can grow up to 6 feet and weigh around 375 pounds, while adult females can grow around 6 feet and weigh around 330 pounds. Harbor seals coloration varies from light gray or silver to dark gray or brown to black. Their coat markings can range from dark spots to white rings. Most spots can be seen on the backside. Seals lack external ear flaps, but have internal ear holes, which will be closed when diving. Harbor seals move their rear flippers in order to move through the water. Harbor seals can sleep on land or in the water.