The guanaco (Lama guanicoe), cougar, the Patagonian fox (Lycalopex griseus), Patagonian hog-nosed skunk (Conepatus humboldtii), and Magellanic tuco-tuco (Ctenomys magellanicus; a subterranean rodent) are the most characteristic mammals of the Patagonian plains.[31] The Patagonian steppe is one of the last strongholds of the guanaco and Darwin's rheas (Rhea pennata),[32] which had been hunted for their skins by the Tehuelches, on foot using boleadoras, before the diffusion of firearms and horses;[33] they were formerly the chief means of subsistence for the natives, who hunted them on horseback with dogs and bolas.