Like its two North American relatives, the Chihuahuan Grasshopper Mouse hunts rather than gathers: it pursues crickets, spiders, and even other small rodents, and stands on its hind feet to emit a sharp howl before dispatching large prey. It lives in the Chihuahuan Desert, a strip shared between the southwestern United States and northern Mexico. For years it was confused with the Desert Grasshopper Mouse (Onychomys torridus), but was separated as its own species due to chromosomal differences. It is the most geographically restricted of the three American Grasshopper Mice.
It has a compact body, fur that is greyish-brown or pinkish above and white below, and a short, thick tail with a white tip. Its overall shape is similar to its two relatives, but its size is intermediate between them. It is easily confused with the Northern Grasshopper Mouse (O. leucogaster), which is slightly larger, and the Desert Grasshopper Mouse (O. torridus), which is similar in size. Reliable separation of these three species depends on cranial or chromosomal characteristics rather than external appearance.
Tracks show four front toes and five hind toes. They are more compact than those of a similarly sized Peromyscus and lack the drag mark typically left by the long tail of the latter, as the Chihuahuan Grasshopper Mouse's own tail is short. Droppings, less than 1 cm long, often contain clearly visible hard arthropod fragments. The most characteristic sign, shared with the rest of the genus, are prey remains (legs, elytra, scorpion stingers) found next to the burrow entrance. This is because the Chihuahuan Grasshopper Mouse typically consumes only the soft parts.
Chihuahuan Desert and arid scrub with loose soils, in the southwestern United States (New Mexico, western Texas) and north-central Mexico.
Insects and other arthropods, including scorpions, along with small vertebrates occasionally; actively hunts instead of gathering seeds.
Solitary and territorial, it marks its territory with a characteristic high-pitched howl emitted while standing on its hind feet. It does not hibernate and remains active throughout the year.
It is considered common, with a stable population within its range, restricted to the Chihuahuan Desert, with no documented signs of decline.
Habitat loss of desert scrub due to agricultural and urban expansion in some areas of its range.
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