Castoroides ohioensis at the Field Museum.

Castoroides, or giant beaver, is an extinct genus of enormous beavers that lived in North America during the Pleistocene. C. leiseyorum and its northern sister species C. ohioensis, were the largest beavers to ever exist.

Giant beaver in A Different Flesh[]

Beavers near big as bears, imported from America, were on display in the London zoo when Samuel Pepys visited there on May 13, 1661.[1]


  1. See e.g. A Different Flesh, p. 52, 2018 edition.