The Harbor Seal (Phoca vitulina) belongs to the family Phocidae (Hair Seals). Members of this family are sometimes called earless seals or true seals, and are the most abundant and widespread of the aquatic carnivores, with representatives found throughout most of the world's seas and some freshwater lakes. Hind flippers are permanently turned backward and are almost exclusively for aquatic use, and fore flippers are smaller than those of the eared seals or the Walrus. There is no external ear, only a small orifice. The fur is stiff, but there is little soft underfur. In most species, newborn have a woolly coat, often white, called the lanugo; it is usually shed within a month and replaced with adult pelage better adapted to a cold climate. Most species are gregarious but form small groups only; and most are monogamous, pairing up during breeding season. Members of this family are believed to have evolved from otter-like ancestors.
The Harbor Seal (Phoca vitulina) is usually yellowish or brownish with dark spots above. Males and females are about the same size: 4-5.7 feet in length, weighing up to 300 lb.
Harbor Seals spend much time basking on beaches and rocky shores in groups of several individuals to 500. At the first sign of danger they give an alaram bark and dive into water. They can dive to 300 feet and remain submerged up to 28 minutes. They feed when the tide comes in, sometimes ascending rivers with the tide, and haul out at low tide, sleeping high and dry until the next tide.
Feeding mostly on fish, including rockfish, herring, cod, mackerel, flounder and salmon, they eat sometimes mollusks, including, squid, clams, and octopus, crayfish, crab, and shrimp. Some learn to steal fish from nets.
Pups are usually born with adult pelage, having shed the lanugo before birth, and may enter the water within a few days.
Polar Bears, Killer Whales, and sharks are their main predators aside from man; Golden Eagles prey on pups.