Common-Seal

Our Dunvegan seal walk by B℮n on Flickr.

Pinnipednesday - Phoca vitulina Edition

This one is extra-cute. Note the tongue sticking out.

The Harbor Seal (Phoca vitulina) can be found in the northern hemisphere, widely distributed along temperate and arctic coastlines. They are also called the common seal, as they are the most widely distributed of any species of pinniped. There are about 5 to 6 million of them worldwide, so they are not threatened as a general population. However, some sub-populations in the Baltic Sea, Greenland and the Japanese Island of Hokkaido are in danger of being extirpated from those areas.

Harbor Seals have distinctive V-shaped noses, with their nostrils appearing to point down and toward each other. Their coats vary in color from gray, dark brown and tan, each with a unique pattern of spots. Adult males can grow up to 5.3 feet (1.61 meters) long, and weigh around 370 pounds (168 kg). Females are slightly smaller at 5 feet (1.5 meters) in total body length, weighing 192 pounds (87.5 kg). Sexual dimorphism in this species is not as pronounced as in other pinnipeds, but generally males will be darker in color, and heavier-set than the females.

When Harbor Seals “haul out” onto land, they will often rest in poses with their heads and tails raised. They swim fairly great distances in search of food, and will even venture pretty far upstream in rivers to find it. They stay close to shore in general, but have been observed making dives of up to 1,640 feet (500 meters) in depth. They feed on a wide variety of marine life, including fish, crustaceans, squid, mollusks, and shrimp. There are currently five recognized subspecies of Harbor Seal:

  • Phoca vitulina vitulina (Europe and western Asia)
  • Phoca vitulina concolor (eastern North America, questionable genetic evidence for designation as subspecies)
  • Phoca vitulina mellonae (eastern Canada, often in fresh water)
  • Phoca vitulina richardsi (western North America)
  • Phoca vitulina stejnegeri (eastern Asia)

The mating habits of Harbor Seals are not quite as clear-cut as they are in other species of pinniped. Mating appears to take place mostly in the water, as well as any aggressive displays made by males. Pupping and breeding seasons depend on the location of a given population. Harbor Seal populations in more temperate zones will pup and breed in February. Further up north, pupping and breeding will take place later in the year, around June or July. Like other pinniped species, Harbor Seal pups start out with a white natal coat. Unlike other species, however, these pups will lose that coat while still in the womb, and are born with their first adult coat.

Harbor Seals are protected in the U.K. and the U.S., unless a seal is observed to be interfering with fishing nets. They are sometimes caught in fishing nets and drown - around the coast of Norway, becoming entangled in fishing nets accounts for almost half of pup mortality. Harbor Seals are also vulnerable to a distemper virus that takes hold periodically. In 1988 it wiped out about 3,000 of the Harbor Seal population along the U.K. coastlines. Oil spills and other chemical pollutants can also affect the health of Harbor Seal populations.