These seals are named after the harp-shaped markings on their back.
Harp seals can live for up to 35 years.
Body length: 1.6-1.9m, Weight: 130-160kg.
The harp seal has a black head, with a black horseshoe or harp shape on its back. The rest of the body is pale grey. They moult in April and grow new coats.
Pups are born with a white coat, and do not gain their characteristic markings until the age of 12 for females, and seven for males.
Harp seals are found in the Arctic and in the north west Atlantic Ocean. They live in the open sea but are dependant on pack ice for breeding.
There are 3 stocks of harp seals - one breeds in the Gulf of St. Lawrence off the coast of Newfoundland, another breeds north of the Jan Mayen islands in the Greenland Sea, and the third breeds in the White Sea.
Harp seals feed on fish such as herring, cod and capelin, as well as crabs and other invertebrates.
They are fast swimmers, and spend most of the year in the sea. Harp seals migrate south in the autumn and north in the summer, which can be a total of 6,000-8,000km. They are also fast-moving across the ice.
Harp seals are gregarious, particularly during the breeding season, when tens of thousands gather together. They are also found in groups when migrating, feeding and resting.
They can dive to depths of over 275m. Predators include sharks, killer whales, polar bears and walruses.
Females give birth to one pup in late February to late March. The pups suckle on their mother's fatty milk for a period of 2-4 weeks, until they are left to fend for themselves.
Harp seals are not considered to be threatened, although many are killed annually by hunters for fur. The population is estimated to be over two million.