Harp Seal Facts (Pagophilus groenlandicus)

Harp seals are best known for the white fur of their pups.
Harp seals are best known for the white fur of their pups. C.O.T/a.collectionRF / Getty Images

The harp seal (Pagophilus groenlandicus), also known as the saddleback seal, is a true seal best known for its adorable furry white pups. It gets its common name from the markings resembling a wishbone, harp, or saddle that develop on its back in adulthood. The seal's scientific name means "ice-lover from Greenland."

Fast Facts: Harp Seal

  • Scientific Name: Pagophilus groenlandicus
  • Common Name: Saddleback seal
  • Basic Animal Group: Mammal
  • Size: 5.9-6.2 feet
  • Weight: 260-298 pounds
  • Life Span: 30 years
  • Diet: Carnivorous
  • Habitat: North Atlantic and Greenland Sea
  • Population: 4,500,000
  • Conservation Status: Least Concern

Description

All seal pups are born with a yellow coat, which whitens until its first molt. Juveniles and most females have a silver-to-gray coat with black spots. Adult males and some females develop a darker head and a dorsal harp or saddle marking. Females weigh around 260 lb and are up to 5.9 ft in length. Males are larger, weighing an average of 298 lb and reaching a length of 6.2 ft.

The male harp seal has a harp pattern on its back.
The male harp seal has a harp pattern on its back. Jurgen & Christine Sohns / Getty Images

Blubber insulates the seal's body, while flippers act as heat exchangers to warm or cool the seal. Harp seals have large eyes, each with a tapetum lucidum to aid vision in dim light. Females identify pups by scent, but seals close their nostrils underwater. Seal whiskers, or vibrissae, are highly sensitive to vibration. They give the animal a sense of touch on land and the ability to detect movement underwater.

Habitat and Distribution

Harp seals live in the North Atlantic and Greenland Sea. There are three breeding populations, located in the Northwest Atlantic, Northeast Atlantic, and the Greenland Sea. The groups are not known to interbreed.

Harp seal distribution
Harp seal distribution. Jonathan Hornung

Diet

Like other pinnipeds, harp seals are carnivores. Their diet includes several species of fish, krill, and other invertebrates. The seals display food preferences that appear to be most heavily influenced by prey abundance.

Predators and Hunting

Juvenile seals are eaten by most terrestrial predators, including foxes, wolves, and polar bears. Adult seals are preyed on by large sharks and killer whales.

However, humans are the primary harp seals predators. Historically, these seals were hunted for their meat, omega-3 fatty acid-rich oil, and fur. Today, seal hunting mainly occurs in Canada, Greenland, Norway, and Russia. The practice is controversial, as the demand for seal products appears to be decreasing and the killing method (clubbing) is graphic. In Canada, commercial hunting is restricted to November 15 to May 15, with kill quotas in place. Despite restrictions, the harp seal retains commercial importance. Hundreds of thousands of seals are hunted each year.

Reproduction and Offspring

Each year between February and April, adult harp seals return to breeding grounds in the White Sea, Newfoundland, and the Greenland Sea. The males establish dominance by fighting each other using teeth and flippers. They court females using flipper movements, vocalizations, blowing bubbles, and performing underwater displays. Mating occurs underwater.

After a gestation period of about 11.5 months, the mother usually gives birth to a single pup, although twins sometimes occur. Birth takes place on sea ice and is extremely fast, taking as little as 15 seconds. The mother does not hunt while nursing and loses up to 3 kg of mass per day. At birth, the pup's coat is stained yellow from amniotic fluid, but it quickly turns pure white. The mother stops nursing and abandons the pup when it's time to mate. Birth, weaning, and mating all occur during the same breeding season.

Initially, the abandoned pup is immobile. Once it sheds its white coat, it learns to swim and hunt. Seals gather annually on the ice to molt their coat, which involves shedding both fur and blubber. Juveniles molt several times before achieving an adult pelt. Harp seals can live over 30 years.

Conservation Status

Harp seal are listed as "least concern" on the IUCN Red List, and their numbers are increasing. As of 2008, there were at least 4.5 million adult harp seals. This population growth can be explained by the decrease in seal hunting.

However, the seal population is still threatened by several factors which could severely impact the species in the near future. Oil spills and water pollution subject the species to heavy chemical contamination and decrease its food supply. Seals get tangled in fishing gear, which leads to drowning. Harp seals are susceptible to distemper, prion infections, and other diseases, which may impact mortality rates. The most significant threat is climate change. Climate change causes a reduction in sea ice, forcing seals to move to new areas. Whether the seals can adapt to such change is unknown.

Sources

  • Folkow, L.P. and E.S. Nordøy. "Distribution and diving behaviour of harp seals (Pagophilus groenlandicus) from the Greenland Sea stock". Polar Biology27: 281–298, 2004.
  • Kovacs, K.M. Pagophilus groenlandicus. The IUCN Red List of Threatened Species 2015: e.T41671A45231087 doi:10.2305/IUCN.UK.2015-4.RLTS.T41671A45231087.en
  • Lavigne, David M. in Perrin, William F.; Wursig, Bernd; Thewissen, J.G.M., eds. Encyclopedia of Marine Mammals (2nd ed.). 30 Corporate Drive, Burlington Ma. 01803: Academic Press. ISBN 978-0-12-373553-9, 2009.
  • Ronald, K. and J. L. Dougan. "The Ice Lover: Biology of the Harp Seal (Phoca groenlandica)". Science215 (4535): 928–933, 1982.