Argyrolagus is an extinct genus of South American marsupial from Patagonia, Argentina. Jumping on its hind legs, the 40 centimetres (16 in) long Argyrolagus resembled a gerbil or kultarr. It had a long tail for balance, and a narrow head with a pointed snout. Judging from its huge eyes, Argyrolagus was nocturnal. The form of its teeth suggest that it would have fed on desert plants.