Perognathus flavus
silky pocket mouse

The silky pocket mouse can be found only in western and southwestern North America. Specifically, it can be found as far west as Colorado, as far east as Texas, as far north as South Dakota, and as far south as Mexico.

The silky pocket mouse prefers to live in low valley bottoms with good soils, where they can live among weeds and shrubs and burrow in the sand. However, they are also more tolerant to harsh habitat conditions than other pocket mice; they can be found in rocky areas and hard and stony soils.

Perognathus flavus is one of the smallest mice in North America. It has soft, silky fur, short ears, and a sparsely haired tail. The dorsal area is a pinkish buff, lightly mixed with black. The ventral area is pure white. They have a conspicuous postauricular patch of buffy fur, which is usually twice as large as the ear (ear is 4-7 mm). The total length is 95-118 mm, tail length is 41-58 mm, hindfoot length is 12-18 mm, and weight is 6-9 g. The main things that will differentiate this mouse from other mice is the incredibly soft fur, small size, and relatively large ear patch. Also, the interparietal bone is more narrow than the interorbital breadth of the skull.

The silky pocket mouse constructs burrows at the base of plants like yucca, cactus, or shrubs. There are usually 2-3 entrances to each burrow, and the openings are plugged during the day. The burrows have blind side tunnels used for defecation and food storage. One individual may maintain more than one burrow system. The silky pocket mouse constructs nests out of grasses and weeds. They primarily live underground for the 5 coldest months of the year, and go through periods of torpor that last approximately 48 hours each. Other than these brief periods of torpor, they remain active all winter long and forage above ground almost nightly. The silky pocket mouse is generally sedentary, and tends not to move more than 40-60 m from their burrows.

The food habits of the silky pocket mouse are similar to other small pocket mice, mainly consuming seeds from various grasses and weeds. They also eat some green vegetation and some insects. They have been found to eat pigweed, goosefoot, Russian-thistle, prickly-pear, globemallow, sand-bur, phlox, juniper berries, gaura, and mustard seeds and grasses. The silky pocket mouse feeds primarily on stored seeds during midday to prepare energetically for foraging in early evening. They store much of the food that they find, placing it in their burrows. The silky pocket mouse is adapted to conserve water very efficiently. They rarely, or never, drink water. Instead, they obtain all of the moisture needed for survival through the breakdown of their food (metabolic water).

While there is no special status assigned to the silky pocket mouse, there is an increasing concern for particular subspecies. Certain Californian subspecies (P. longimembris brevinasus, P. inornatus psammophilus, p. alticola alticola, P. longimembris pacificus) are losing a vast amount of habitat due to construction and urbanization.