Penasco Chipmunk from the Department of Game and Fish
What we call least chipmunks are common in New Mexico, and you may see one scamper off with a morsel at your campsite. But to see the Penasco chipmunk you have to travel to the Sacramento Mountains. Chipmunks (Eutamias minimum) and their relatives are the only rodents in New Mexico that have stripes on their backs. Chipmunks also have stripes that extend onto the face, while squirrels have stripes only on their bodies. Chipmunks have bushy tails and are not spotted.
The Penasco chipmunk (E. m. atristriatus), is a subspecies of the least chipmunk. Its body is grayish-brown on the back, and light brown on the flanks, rump and thighs. The belly is white, the feet are pinkish, and the tail is dark. The top of the head is black with flecks of white and cinnamon. There is a white patch behind each ear. The face is white. Eyes and claws are dark. This chipmunk displays dark stripes on the back and head. Individuals are about six inches long, with seven-inch tails. The Penasco least chipmunk is found on Sierra Blanca and elsewhere in the Sacramento Mountains of southeastern New Mexico. It lives in elevations of 7,290 to 8,580 feet above sea level.
This chipmunk lives along the James and Penasco canyons, in and near ponderosa pine forests. There, they are found in open areas that include fence rows bordering fields and thin stands of trees. They are also found as low as juniper woodland and as high as spruce forest.
Least chipmunks are very active during the day, retreating to burrows at night, in cold weather, and to escape danger. They climb well, although much of their activity is spent on fallen timber, rocks, and open ground. Populations living in colder areas hibernate. Foods include weed seeds, sunflowers and cultivated grains, but fruits, nuts, flowers, leaves, insects, and other items are no doubt eaten as well. Young are probably born in mid- to late summer, as halfgrown juveniles have been seen in early September.
The least chipmunk is commonly found throughout New Mexico, but the Penasco subspecies has drastically declined. The reason for the possible extinction of this chipmunk appears to be fewer pastures and agricultural fields. Gray-footed chipmunks may also have out-competed the Penasco subspecies for food and habitat.
If the Penasco chipmunk is to survive in the Sacramento Mountains, the key to its survival is restoration and maintenance of suitable habitat. Population surveys and strict control over the killing of these chipmunks, including for scientific purposes, should continue.