The rock pocket mouse (Chaetodipus intermedius) is one of 19 species of pocket mice in the genus Chaetodipus. (It is sometimes grouped in the genus Perognathus.) Found mainly in rocky outcrops in the deserts of the southwestern United States and Mexico, the rock pocket mouse is medium-sized (length ~18 cm, weight ~12–18g) and nocturnal. It eats mainly plant seeds and makes small burrows in soil close to or under rocks to evade owls, its main predator. The breeding season spans a few months, starting in February or March, and the litter size is typically between three and six. As with most pocket mice, the tail is longer than the body (~10 cm).