Otariids, seals and walruses are the three families of the Pinniped order. Pinnipeds (from Latin penna = flat and pes/pedis = foot) are sea-mammals: they are homeothermic (i.e having high and regulated inner temperature), lung-breathing (i.e dependant on atmospheric oxygen) animals having come back to (semi) aquatic life. Fur seals belong to the otariid family (Otariidae) and so do sea-lions (Otariinae). Compared to sea-lions, fur otaries are usually smaller, thicker-furred and sharper-muzzled - hence their scientific name derived from Greek Arctocephalus, which means bearlike head. Nowadays nine different species of otaries are known, seven of them living in the southern hemisphere.

The Amsterdam fur otary was first described by Gray (1872) who called it Arctocephalus tropicalis. This species mainly breeds in the subantartic islands in the North of the Antarctic convergence, hence its English name of Subantartic fur seal.