The montane guinea pig (Cavia tschudii) is a medium-sized wild rodent with a variable coat colour depending on geographic location, ranging from reddish-brown and black in Peru to pale brown in Chile and agouti olive in Bolivia, with darker or lighter underparts accordingly. These herbivorous animals are found in diverse Andean habitats, from high grasslands to deserts and riparian areas, and are considered an ancestor of the domestic guinea pig.