Aivukus is an extinct genus of walrus from the Miocene.
Etymology The generic name is derived from the Inuit word for walrus, aivuk.
Description From fossil records it was at least as big as, if not slightly bigger than, the modern walrus, and, like the modern walrus, was probably a molluscivore.
Sources
Marine Mammals: Evolutionary Biology by Annalisa Berta, James L. Sumich Encyclopedia of Marine Mammals by William F. Perrin, Bernd Wursig, and J. G.M. Thewissen