phocid

The Walrus, Odobenus rosmarus (1762)

Phylum : Chordata
Class : Mammalia
Order : Carnivora
Suborder : Pinnipedia
Family : Odobenidae
Genus : Odobenus
Species : O. rosmarus
Subspecies : O.r. rosmarus, O.r. divergens, O.r. laptevi

  • Least concern
  • 4,5 m long and 1 700 kg (size)
  • Arctic circle (map)

The walrus is a mammal in the order Carnivora. It is the sole surviving member of the family Odobenidae, one of three lineages in the suborder Pinnipedia along with true seals (Phocidae) and eared seals (Otariidae). While there has been some debate as to whether all three lineages are monophyletic, i.e. descended from a single ancestor, or diphyletic, recent genetic evidence suggests all three descended from a caniform ancestor most closely related to modern bears. Recent multigene analysis indicates the odobenids and otariids diverged from the phocids about 20–26 million years ago, while the odobenids and the otariids separated 15–20 million years ago. Odobenidae was once a highly diverse and widespread family, including at least twenty species in the Imagotariinae, Dusignathinae and Odobeninae subfamilies. The key distinguishing feature was the development of a squirt/suction feeding mechanism; tusks are a later feature specific to Odobeninae, of which the modern walrus is the last remaining species.

Walrus photo