The olive-backed pocket mouse is an occasionally recorded rodent of Colorado’s dry, open country. Open occurrence databases hold 128 Colorado records, and NatureServe rates the species vulnerable here. It is a northern-plains seed specialist, not a Southwest desert mouse, and Colorado sits squarely in its range.
Grassland and sage, on both slopes
This little rodent keeps to shortgrass prairie, sagebrush flats, and sandy draws rather than mountains or true desert. Its Colorado records reflect that, splitting between the sage country of the northwest, heaviest in Moffat County, and the foothill and plains grasslands to the south and east in Custer, Fremont, Weld, and El Paso counties. It carries food in external, fur-lined cheek pouches that open outside the mouth, so gathered seeds stay dry as the mouse hauls them underground. That single feature drives its life: quick surface trips after loose grass and forb seeds, then a fast retreat to a burrow cache before an owl, snake, or fox finds it in the open.
A nocturnal life that shuts down for winter
The olive-backed pocket mouse is strictly nocturnal, and its record follows a sharp seasonal rhythm the shrews and voles do not share. It is absent from the cold-weather record entirely, because it spends the winter underground in torpor, living off cached seed rather than braving frozen, foodless ground. Records appear as the ground warms and the animal resumes its nightly foraging, then taper as it returns underground for the cold months. So the gaps are real biology, not missing observers: this is a seed-caching rodent that meets a hard plains winter by sleeping through it, tucked in a burrow with its harvest.
Full species profile
