Pinyon mice are medium-sized mice that are often distinguished by their relatively large ears. Their fur varies in color from a pale yellowish brown to a brownish black color, and their feet are a lighter color, varying between dusky and white. These mice have tipped tails with long hairs and a dark dorsal stripe along its length. Males and females in this species are similar in size.
Pinyon mice are native to the southwestern United States and Baja California in Mexico. They range from southern Oregon and Wyoming in the north, and extend south to roughly the U.S.-Mexico border, with a disjunct population that occupies an area in the vicinity of Palo Duro Canyon in the Texas panhandle. Pinyon mice can be found in a variety of habitats. Although they prefer rocky slope areas and pinyon-juniper areas, they are also found in desert, forest, and grassy plains, riparian woodlands, as well as landscapes including canyons, redwoods, sagebrush, scrub oak and cacti. These mice are flexible in habitat elevations and able to adjust to varying climate conditions.
Pinyon mice are solitary and nocturnal creatures. They sleep periodically during the day in their dens. They make dens under rocks, stone shelves and slabs, and in trees. Pinyon mice are territorial. Male territories are larger and female territories are smaller. Within these territories, male dens are usually located farther apart from each other than female dens. Pinyon mice are very good climbers and often forage in trees. They have acute senses of hearing and smell, which they use during foraging, to navigate, and escape predators at night.
Pinyon mice are omnivores and feed on insects, invertebrates, berries, nuts, and fungi. Finding water is usually a challenge in most of their habitats and they adjust their diet accordingly.
Pinyon mice are polygynandrous (promiscuous), which means that both males and females have multiple mates. Females nest in small territories and males try to find mating opportunities with nearby females. Pinyon mice breed from mid-February to mid-November with a peak between April-June. Females give birth to 3 litters with 3-6 pups. Gestation lasts around 26-40 days. Pups weigh around 2.3 grams at birth, and they are born hairless with their ears and eyes closed. Mothers nurse their young for 3-4 weeks, after which they become independent. Females in this species are ready to breed at around 50 days of age, and males - at around 9 weeks of age.
Currently Pinyon mice do not face any serious threats.
According to IUCN, the Pinyon mouse is very abundant, and widespread throughout its range but no overall population estimate is available. Today, this species’ numbers are stable and it is classified as Least Concern (LC) on the IUCN Red List.