Hooded Seal, Cystophora cristata

The hooded seal, Cystophora cristata, is large, measuring 1.8–2.8 m and weighing up to 410 kg. Their most remarkable feature is the crescent-shaped "hood" that males can form on their nose by inflating their nasal cavity. This hood is essentially a fleshy sac which is alternately inflated with air and then allowed to collapse. It is used by males to distinguish each other and to establish dominance.

A collapsed hood.
An inflated hood.

Hooded seals are a migratory species and live between the large masses of drifting sea ice and the open sea. In the southern parts of their range, they give birth and breed in the early spring. In mid-March, pregnant females haul themselves onto the pack ice to give birth. The pups, called "bluebacks," have a shiny, blue-black coat with a cream-coloured underside. Pups are weaned very quickly, in about ten days, after which time the mothers are ready to breed again. Mating normally occurs in the water, where males actively compete for females. Some males are able to guard several females – a harem, while others are only able to guard a single mate. Females reach sexual maturity between 3 and 7 years of age, but males do not mate until 10 years of age.

Hooded seals are opportunistic feeders, taking advantage of the most abundant species at a particular time of season. They often engage in deep dives to feed on deepwater fishes such as redfish, capelin, halibut, flounder, polar cod, and even squid.

A male hooded seal, Cystophora cristata.
A female hooded seal, Cystophora cristata.