The coat is usually heavy, with a dense underfur and long guard hairs. The head, ears, and neck are often reddish. The underparts are usually pale. The tail is long, bushy, and black-tipped. Dens are usually among rocks, under bases of trees and low shrubs, or in burrows made by other animals, such as viscachas and armadillos.
Most activity is nocturnal, but some individuals are occasionally active during the day.
P. gymnocercus sometimes collects and stores objects, such as strips of leather and cloth. The omnivorous diet includes rodents, lagomorphs, birds, lizards, frogs, insects, fruit, and sugar cane. Studies of stomach contents indicate that P. gymnocercus takes an equal amount of plant and animal food. P. culpaeus seems to be more carnivorous than other species and reportedly sometimes preys heavily on introduced sheep and European hares. In western Argentina, during the spring part of the population of P. culpaeus shifts 15-20 km into the higher mountains, in response to the seasonal movements of the sheep and hares.