The Cactus mouse (Peromyscus eremicus) is one of eight species in the genus Peromyscus that inhabit Arizona. All are similar-looking grayish-brown, with white bellies and feet, and large ears. They are about 3.5 inches long. The cactus mouse has a sparsely furred tail with a slight tuft at the tip. “Females weigh slightly more than males and are significantly larger in body length, ear length, length of mandible and bullar width of skull. Cactus mice can be identified by having naked soles on their hind feet, and almost naked tails which are usually the same length or longer than the animals body length.” (Source)
The Cactus mouse ranges from southern California and Nevada, through southern Arizona and New Mexico, west Texas into northern Mexico. They are common in washes and rocky hillsides, in sandy deserts and desert foothills. Depending on location, they may breed throughout the year. A female may produce 3 to 4 litters per year, each with 4 to 5 young.
Cactus mice are nocturnal feeders. They eat seeds, fruit, and succulent plant material. Their diet includes mesquite beans and leaves, and insects. During the day they remain in burrows in clumps of cacti, in the ground, or among rocks. Their nests are usually a ball of grasses or twigs.
According to the Arizona-Sonora Desert Museum:
“The cactus mouse often climbs around in vegetation and brush, searching for seeds and fruits to eat. It may nest in wood piles or rock piles, or use the abandoned burrows of other animals. Although this mouse needs less water than many others and is desert-adapted, it may estivate or go into a torpor in the summer when resources for food and moisture are not available.”
“These little rodents are at the bottom of the vertebrate food chain, preyed upon by everything from coyotes and snakes to hawks and bobcats. In response, they breed prolifically, with some species, like the cotton rats, able to produce eight to ten litters a year. Populations still fluctuate with drought and predation, but the mice and rats are able to respond to good conditions by rapidly rebuilding their numbers.”
“All rodents, including the mice and rats, are gnawers. Their teeth are ever-growing and must be kept trimmed down by constant gnawing. A layer of hard orange enamel covers the front surface of the teeth. The rest of the tooth is softer and wears down quicker than the enamel as the rodent gnaws, thus creating a chisel-like shape to the front teeth that is unique to the rodent family.”
Other desert rodents: