By Rebecca Yoo
Geographic Range
Hooded seals are found throughout the northern part of the Atlantic Ocean near Labrador and northeastern Newfoundland, south to New England. Wandering individuals have been recorded from as far south as Puerto Rico and the Virgin Islands. (IUCN, 2008)
Biogeographic Regions:
nearctic 
(native ); atlantic ocean (native ).
Habitat
The hooded seal lives mainly on large ice packs and in the deep waters of the Atlantic Ocean (Parker 1990).
These animals are found in the following types of habitat:
temperate ; saltwater or marine .
Aquatic Biomes:
coastal .
Physical Description
(660 to 880 lbs)
(8.2 ft)
The hooded seal has a black head and a dark clouded spotted pattern on grayish colored fur. Males are approximately 2.5 m and weigh around 400 kg, while females are slightly smaller. The most unusual physical characteristic if the hooded seal is the inflatable trunks of males. The trunk is a large flap that hangs in front of the head in front of the mouth. It can be inflated when the male is mating, excited, or threatened. The hooded seal also has large claws on its front flippers (Parker 1990).
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Sexual dimorphism: male larger, ornamentation .
Reproduction
The mating system of hooded seals is not well understood, but indications are that males practice sequential female-defense polygyny.
Mating systems:
polygynous .
Hooded seal pups are born during March and April after a gestation period of 11.7 months, which may also include a period of four months when the fertilized egg is dormant and does not develop. Hooded seals usually give birth to one pup at a time. The pup weighs 15kg at birth and is weaned after only four days of nursing due to the high fat content of the milk. The pups lack an embryonic coat at birth and are blue in color with light gray bellies and black faces. After a year, the pups become spotted like the adults.
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
Behavior
The most unusual behavior of the hooded seal is related to the males' trunks. When a male is mating, excited, or threated, the trunk is inflated. To accomplish this, the male closes one of his nostrils, resulting in the trunk blowing up to as large as twice the size of a football. The inflated trunk forms a crest or a hood on top of the head (Parker 1990). This trunk begins to form in young males around 4 years of age and is finished developing at around 12 years. The size of the trunk depends on the body size of the individual, but the average is 6.3 liters. The hooded seal is mainly a solitary animal, but families are encountered during the reproductive season (Nowak 1991).
Key behaviors:
natatorial ; motile ; nomadic ; solitary ; social .
Food Habits
The hooded seal eats mainly deep water fish including redfish, Greenland turbot, herring, capelin, cod, halibut, and flounder. Its diet also includes shrimp, octopus, and mussels.
Primary Diet:
carnivore (piscivore , molluscivore ).
Animal Foods:
fish; mollusks; aquatic crustaceans.
Economic Importance for Humans: Positive
Hooded seals are mainly hunted for their spotted coats as well as the blue coats of the pups. Also, in some areas of the world the hooded seal is hunted for its meat and oil (Nowak 1991).
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
The total population of hooded seals is not at risk even though it is subject to hunting.
Other Comments
The enemies of the hooded seal are humans, polar bears and sharks (Nowak 1991).
For More Information
Find Cystophora cristata information at
Contributors
Rebecca Yoo (author), University of Michigan.
