Fur seals are any of nine species of pinnipeds in the Otariidae family. One species, the northern fur seal (Callorhinus ursinus) inhabits the North Pacific, while seven species in the Arctocephalus genus are found primarily in the Southern Hemisphere. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively long and muscular foreflippers, and the ability to walk on all fours. They are marked by their dense underfur, which made them a long-time object of commercial hunting.