An arctic seal in which males have a bizarre inflatable 'hood' on their heads, and can also inflate their nasal cavity out through their nostrils like a red balloon.

Subspecies
Two stocks, but not recognised as subspecies (one in NW Atlantic, one in the Greenland Sea).

Life span
30-35 years.

Statistics
220-250cm, weighing 350-435kg (females smaller than males).

Physical description
The coat is silvery grey and covered in black blotches. The flippers and head are darker. Pups are born with blue-grey backs and silvery or yellowish sides, a dark face and dark flippers. Males have an inflatable 'hood' on top of their heads and can also inflate their nasal cavity through one or both nostrils, looking like a red balloon.

Distribution
North West Atlantic, Greenland Sea but ranging as far east as Ireland, as far south as Portugal and occasionally from the Atlantic down to California and Puerto Rico.

Habitat
Arctic waters and sea ice.

Diet
Deepwater fish and squid.

Behaviour
Hooded seals are generally solitary except during the breeding season and when moulting from June to August.

Reproduction
Breeding occurs in the second half of March, when females haul out onto drifting pack ice to give birth. They have a single pup, which is fed with milk containing 50 per cent fat, causing them to grow 5kg per day. They are weaned in only 4 days by which time they weigh around 40kg. During this short period, aggressive males display and fight for the right to mate, with the largest usually gaining many matings each.

Conservation status
Currently hooded seals are not thought to be threatened, although changes to the Arctic ice because of global warming is a concern.

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