About Hooded Seals

Hooded Seal

Description & Behaviour

The Hooded seal, Cystophora cristata, is named for the large elastic sac that extends from the nose to the forehead that expands into a large balloon-like ball in adult males. Hooded seals have a black face and a blue-gray coat with patterns of dark patches. Adult males measure an average of 2.5-3 m in length and weigh about 300-400 kg. Adult females are smaller, measuring an average of 2-2.4 m in length and weighing about 160-230 kg. Hooded seals are known to dive repeatedly to over 1,000 m for more than 50 minutes. The life span of the Hooded seal is 30-35 years of age.

Hooded seals are very aggressive compared to other seal species. Adult males demonstrate their aggression by inflating their "hood" (balloon-like ball on their face), which can grow to twice the size of a football. The "hood" is an enlargement of the nasal cavity which develops at about 4 years of age. When inflated, the hood forms a balloon on the head, when deflated the hood hangs in front of the upper lip. Males also have an inflatable nasal membrane that expands like a red balloon from one nostril that "pings" when shaken. The hood and membrane are used for aggression display when threatened and as a warning during the breeding season.

World Range & Habitat

The Hooded seal is found in deep waters in the far north Atlantic Ocean. This species ranges from Svalbard in the east to the Gulf of St. Lawrence in the west. Four distinct populations can be found on the pack ice: (i) near Jan Mayen Island, (ii) off Labrador and north-eastern Newfoundland, (iii) in the Gulf of St. Lawrence, and (iv) in the Davis Strait. The total hooded seal population is currently estimated to be 650,000, consisting of 250,000 in the Jan Mayen population and 400,000 in the northwest Atlantic Ocean. This is a highly migratory species known to wander long distances as far west as Alaska and as far south as the Canary Islands and the Caribbean island of Guadeloupe.

After the breeding season, usually from April-June, these seals travel long distances to feed. In June-August they reunite on the ice to molt after which they disperse to feed until breeding season begins in late winter. Migratory patterns are not yet well documented, however the northwest Atlantic populations appear to molt off the east coast of Greenland in the Denmark Strait then travel north. They are also seen along the coast of western Greenland. Individuals from the Jan Mayen population appear to molt on two sites north of the breeding area then disperse to feed in Svalbard, Iceland, Norway, and the Faroe Islands. The northwest Atlantic populations are thought to winter in waters off Newfoundland.

Feeding Behavior (Ecology)

Hooded seals, Cystophora cristata, feed in deep water diving to depths of 100-600 m. Their diet varies regionally and includes: Greenland halibut, redfish, cod, wolffish, capelin, and herring. Octopus, squid, shrimp and mussels are also eaten.

Predators: Polar bears, Greenland sharks, and Orca (Killer whales), people/sealers.

Life History

Female Hooded seals mature between 3-6 years, males at 5-7 years. The amount of interchange between the different breeding populations of this highly migratory species is unclear, although a sighting of a Harp seal-Hooded seal hybrid pup has been reported.

Pups are born between March-April with a well-developed blubber layer and a blue-gray coat, which led to their nickname "blueback". They will molt this coat in about 14 months. Newborn pups measure about 1 m and they weigh about 24 kg. Nursing only lasts an average of 3.8 days, the shortest lactation period of any mammal. In spite of the short nursing period, the pup doubles in size from about 24 kg to about 47 kg thanks to mother's rich milk made up of between 60-70% fat. When the females start giving birth, the begin males competing for breeding territory by pushing and fighting each other. Males then wait to mate while the female nurses forming temporary "families" or "triads". When the pup is weaned, the male and female mate in the water. Several hours after mating, the male returns to the breeding territory in search of another female.

Comments

Hooded seals were commonly killed for their pelts, and juvenile "bluebacks" were particularly valued. In 1983, public pressure prompted the European Economic Community to ban the import of blueback products, and Canada has prohibited the commercial hunting of bluebacks since 1987. Unfortunately, illegal killing has continued. Canadian authorities seized 22,846 dead bluebacks following a hunt in 1996.

Hooded seals suffer from entanglement in gillnets in Iceland, Newfoundland, Labrador, and in the north-eastern US. Like other seal species, Hooded seals have been blamed for reduced fish stocks, and the fishing industry has called for culls.

Records

Hooded seals have the shortest lactation period of any mammal at only 4 days.

Hooded seal pup - also knows as a "blueback". They begin to molt this coat at about 12-14 months of age. Bluebacks are illegal to hunt in Canada.

Adult males demonstrate their aggression by inflating their "hood" (balloon-like ball on their face), which can grow to twice the size of a football.

Hooded seal family. The male in the background, then the female and her pup.

Hooded seals are very aggressive compared to other seal species.