The skull is smaller and narrower than that of Goldman's pocket mouse (Chaetodipus goldmani) which is native to the same parts of Mexico.

The reason for this may lie in the fact that the soil is darker in this area and pale individuals are more easily spotted by diurnal predators.

[3] The narrow-skulled pocket mouse is endemic to Mexico and is found in the states of Chihuahua, Sonora, Durango and Sinaloa.

In Chihuahua it is restricted to rocky areas and canyons while in Durango it occurs in humid tropical forests on the western foothills of the Sierra Madre Occidental.

[3] The narrow-skulled pocket mouse is common throughout much of its wide range and its total population size is presumed to be large.