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Cystophora cristata

Hooded Seal

Order: Carnivora
Family: Phocidae

Image of Cystophora cristata
Cystophora cristata - female and pup on ice floe; males in water, from left to right: normal, extruded nasal septum, and inflated hood
Click to enlarge. (92 kb)

Conservation Status: Vulnerable. There have been dramatic population declines in the northeast Atlantic for unknown reasons.

Male hooded seals have a fleshy sac above the nostrils that they can inflate. It grows as the animal gets older, and looks a lot like a hood over the nose—thus the name "hooded seal." The seals can also inflate the strip of flesh that separates the nostrils. Blown up, it looks like a red balloon. Males use these structures to attract females, or perhaps to threaten other males, or both. They mate with several females, and protect each female and her offspring from other males while the pups are nursing. Nursing lasts only four days, and in that time, the pup doubles its birth weight, gaining 7 kg per day, mostly in blubber, by feeding on milk that is twice as rich in fat as whipping cream. After four days, the mother leaves her pup, who lives on the stored fat for several weeks, until it is old enough to swim and catch fish to eat.

Also known as:
Crested Seal, Bladder Seal

Sexual Dimorphism:
Males are almost twice as heavy as females.

Range: 2.3-2.9 m males; 2-2.3 m females

Average: 250 kg males; 180 kg females
Range: up to 435 kg males; up to 350 kg females


Erxleben, J.C.P., 1777.  Systema regni animalis per classes, ordines, genera, species, varietas, cum synonymia et historia animalium.  Classis I, Mammalia,  1:590.  Wegand, Leipzig, 636 pp.


Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Cystophora cristata

Image of Cystophora cristata
Click to enlarge. (66kb)