The hooded seal (Cystophora christata) is an arctic seal, which is named after a cap-like bulge essay on forehead and nose of the male that doesn’t hang down as with the elephant seal. The bulge develops when the seal is four years old. The male can blow up this bulge, so that the size of its head seems to be twice as large.

The male of the hooded seal is about two and a half meters long and weighs 300 kg. Females are smaller: They measure about 2 m and weigh 200 kg. The colour is silvery; the body is scattered with dark, irregular marks. The head is darker than the rest of the body, and without marks.