The
northern elephant seal (
Mirounga angustirostris) is one of two
species of
elephant seal (the other is the
southern elephant seal). It is a member of the
family Phocidae ("true
seals"). Elephant seals derive their name from their great size and from the male's large
proboscis, which is used in making extraordinarily loud roaring noises, especially during the mating competition.
Sexual dimorphism in size is great: The males can grow to and , while the females grow to and . Correspondingly, the mating system is highly
polygynous; a successful male is able to impregnate up to 50 females in one season.