Standing between 1,100 to 1,200 mm at the shoulder, Guanacos have slender bodies with long limbs and neck. They are herbivores that can inhabit dry areas and forego drinking for long periods. They are versatile foragers, both browsing and grazing on grasses and plants.

Their numbers have drastically reduced due to human pressures of habitat encroachment, habitat destruction, and hunting for their meat and fur. In addition, climatic changes are also blamed for decreases in population size and range.