The Ross seal shares a recent common ancestor with three other extant Antarctic seals, which are together known as the lobodontine seals. The other species are the crabeater seal (Lobodon carcinophaga), leopard seal (Hydrurga leptonyx) and Weddell seal (Leptonychotes weddelli). These species, collectively belonging to the seal tribe Lobodontini, share teeth adaptations, including lobes and cusps useful for straining smaller prey items out of the water column.