Gray Seal
 

Common Name: Gray Seal

Class: Mammalia

Order: Pinnipedia

Family: Phocidae

Genus: Halichoerus

Species: Halichoerus grypus

 

Taxonomy/Description

Gray Seals belong to the Mammalian Order Pinnipedia, in the family Phocidae.  Other members of Phocidae include elephant seals, harbor seals, and monk seals.  Phocids are referred to as true seals.  They are distinguished from other pinnipeds by their inability to support their body using their hind limbs.  The Gray Seal's scientific name, Halichoerus grypus, means "hook-nosed sea pig".

Gray seals are generally 8-10 feet in length, with males weighing about 770lbs and females weighing about 440lbs.  They range in color from gray to almost black.  Their stomachs are paler in color, an aquatic adaptation called countershading.  Males are usually dark with lighter splotches, females are light with dark splotches.

Habitat/Diet

Gray seals can be found in the northern Atlantic waters along the coast of Canada, Greenland, and northern Europe. Gray seals feed on bottom-dwelling fish, squid and octopus.

Behavior/Reproduction

The gray seals gather in groups to feed.  They can dive to depths of 475ft, remaining submerged for 20 minutes at a time.  This is achieved by a combination of adaptations.  Gray seals have large amounts of hemoglobin in their blood, storing large amounts of oxygen.  Their heart rate also slows down, slowing the amount of oxygen used by the body.  A thick layer of blubber enables gray seals to survive in frigid waters.

Like most other seals they do not make long migrations. The breeding season varies depending on location.  During the 4 to 6 week breeding season, males and females will not hunt or eat.  The males do not defend territories, but instead maintain harems of females.  They maneuver better on land than other members of its family and may crawl far inland to give birth.  Newborn pups weight 30lbs.  The seal pup gains three pounds each day until it is weaned.  At 4-5 weeks the pup sheds its white coat and enters the water, beginning its life at sea.  Males may live up to 30 years, with females reaching 40 years of age.

Conservation

Seals have been hunted for thousands of years for food and blubber. Recently, pups have been killed for their white fur, which is used in the fashion industry.  Fortunately for the gray seal, the efforts of conservationists have halted the slaughter of seal pups.  Gray seals are also unpopular with fishermen.  Some fishermen claim they destroy fishing gear, consume great quantities of fish, and host codworms.  Codworm larvae reduce the commercial value of fish. However, scientists claim gray seals do not seriously reduce the number of fish.  Once rare, the gray seal is now more common due to protective laws.  Some locations have seen quite an increase in gray seal numbers.  Water pollution, fishing gear, and physical waste still threaten the gray seal.

 

Content provided by Canisius College students under the direction of Michael Noonan, PhD.