Family: Phocidae, Hair Seals view all from this family
Description Highly variable in coloration; two main color types: white, light gray, yellowish gray, or brownish; with dark spots: and black, gray, or brown with light rings. Most often yellowish gray or brownish with dark spots; spotted creamy white below. Sometimes colored with an orange, rust, or green cast (found on one-fifth of the animals in San Francisco Bay), possibly due to algal growth. Nostrils close together, V-shaped. Male larger than female. L male 4' 7"–6' 2" (1.4–1.9 m), female 3' 11"–5' 7" (1.2–1.7 m); T 3 3/8"–4 1/2" (8.7–11.5 cm); Wt male to 308 lb (140 kg), female to 175 lb (80 kg).
Similar Species Very similar Spotted Seal also occurs in se Bering Sea and is best identified by habitat, preferring pack ice rather than islands or mainland. Northern Elephant Seal is larger and lacks spots. Gray Seal is often splotched, and young are very similar to Harbor Seal. Gray Seal has less dog-like face; eyes are farther from nostrils; and nostrils, when viewed head-on, are farther apart, appearing as a W rather than a V. Ringed Seal has streaks in a marbled pattern as well as spots.
Breeding Breeding season varies; 1 pup born March–August, with adult fur; weighs 18–26 lb (8–12 kg).
Habitat Coastal waters, mouths of rivers, beaches, and rocky shores; some northern populations permanently inland in freshwater lakes.
Range n West: s Arctic from Yukon and n Alaska south along California coast. In East: s Greenland and Hudson Bay coasts south to Carolinas.
Discussion The gregarious Harbor Seal spends much time basking on beaches and rocky shores, sometimes alone but usually with several other individuals, and occasionally in groups numbering in the thousands. Whether alone or in a group, it stays alert to danger; a single seal spends much more time watching for danger than does one that is part of a group. At the first sign of trouble, it gives an alarm bark and dives into the water. The Harbor Seal can dive to 1,460 feet (446 m) deep and remain submerged for 27 minutes. It feeds mostly on fish, including rockfish, herring, cod, mackerel, flounder, and salmon, but it eats some mollusks (about 5 percent of the diet), such as squid, clams, and octopus, and sometimes crayfish, crab, and shrimp. Some seals learn to steal fish from nets, often damaging them and incurring the wrath of commercial fishermen. This species feeds when the tide comes in, sometimes ascending rivers with it, and in the spring may follow fish runs up a river for hundreds of miles, returning to coastal waters in the fall. The animal hauls out at low tide, sleeping high and dry until the next rising tide unless disturbed. The Harbor Seal becomes sexually mature at three to seven years of age. Pups are usually born with adult fur, having shed the lanugo before birth. They are often born in the intertidal zone and can follow the mother on land or into the water within five minutes of birth. The young’s vocalizations keep the mother and young in contact. A pup often stays on the mother’s back while she dives. A female may lose more than 35 percent of her weight during lactation, which lasts about four weeks. She mates within a few days after weaning the young. An individual Harbor Seal may live for 30 or more years. Polar Bears, Northern Sea Lions, killer whales, and sharks are the main predators aside from humans; golden eagles sometimes prey on pups.
