Description: The silky pocket mouse is a small, delicate mammal that can be distinguished from other rodents by: 1) light yellowish to reddish-buff pelage intermixed with black hairs, 2) conspicuous pale yellowish patch of hair behind each ear that is at least twice the length of the ear, 3) soft, long, silky hair, 4) white underparts, 5) tail slightly darker on the dorsal surface but lacking a distinct stripe, 6) fur-lined external cheek pouches which open on each side of the mouth, and 7) grooved upper incisor teeth. Sexes are alike and seasonal color variation is minimal. Immatures are duller in color than adults.
Size: Adults may attain the following dimensions: total length 100-119 mm; tail 44-57 mm; hind foot 15-16 mm; ear 6-7 mm; weight 6-10 grams.
Range and Habitat: The silky pocket mouse occurs in the arid western half of the state. Specimens were collected from Riley County in the late 1800's but the species probably does not exist there presently. This mouse inhabits sandy soils associated with river banks among sparse stands of weeds and shrubs, and shallow loamy upland soil with a well-developed cover of prairie grasses.
Reproduction: Very little is known about the reproduction and habits of this mouse in Kansas, but elsewhere it produces a single litter per year of two to six young. Some females may produce a second litter late in the summer. The gestation period is probably about 28 days.
Habits: Silky pocket mice are strictly nocturnal, foraging from late twilight to near daybreak. They spend the daylight hours in a series of shallow subterranean runways including a nesting are which is used for shelter and rearing young. Other chambers are used for storing grass seeds. Entrances to underground tunnels, which are just large enough to allow the mouse to enter, are usually placed near the base of weeds or shrubs and are characterized by slight mounds of soil. In daytime they are plugged with soil to keep out snakes and other predators, and to keep the burrows cool. When blowing soil completely covers these plugged holes, evidence of the underground retreats is erased. Dry, sandy to loamy soils are generally preferred by this mouse. The sandy color of this mouse's pelage serves as camouflage. Although it inhabits dry areas, its water requirements are satisfied by moisture from food, and by metabolic water.
Food: Grass seeds are the principal food although some green vegetation is also consumed. Seeds are usually husked before being eaten.
Remarks: Snakes, owls, weasels, skunks, foxes and coyotes are the main predators of the silky pocket mouse. Maximum longevity of this mouse is probably two to three years in nature, and five or more years in captivity.