White-throated Woodrat
Order Rodentia : Family Muridae : Neotoma albigula Hartley

Description. A medium-sized woodrat with large ears, bulging black eyes and relatively short, distinctly bicolor tail (grayish brown above, white below), densely covered with short hairs; throat, and usually breast and chin, with hairs white to base; upperparts dull pinkish buff, brightest along sides, thinly suffused with blackish; underparts and feet white. External measurements average: total length, 328 mm; tail, 152 mm; hind foot, 34 mm. Weight, 136-294 g.

Distribution in Texas. Found in Panhandle and broken country south of Red River to Bexar and Uvalde counties, and westward throughout much of the southwestern part of state.

Habits. This woodrat is characteristic of the brush lands of the southwestern deserts. The availability of such desert shrub vegetation as prickly pear, cholla cactus, mesquite, sotol, lechuguilla, and creosote bush which afford shelter for their houses, seems to affect their abundance more than the nature of the terrain. Cholla cactus and prickly pear offer preferred home sites because they supply not only protection but also food and water. Occasionally, their houses are built in the open or in sparse vegetation. In rocky situations the associated cracks and crevices afford the usual den site.

The house is a crude cone of sticks, cactus joints, and other rubbish which surrounds the nest proper — a compact, cup-shaped structure composed of shredded dry leaves, blades of grass, and weed stems. Access to the house is by means of openings near the base to which well-worn trails lead. Frequently, especially in localities where building materials are scarce, the house is supplemented by a system of underground burrows.

Although several houses may occupy a small, desirable patch of cacti, the rats are not social creatures. Only one animal or a female and her young occupy each house. Their home range or feeding territories overlap considerably, but to each rat his house is a personal affair and thus is not shared.

The menu of these rats consists of a variety of desert plants, but the cactus family led the list of more than 30 items found in the stomachs of 360 rats examined. Mesquite and forbs were next in preference. Grasses constituted less than 5% of their fare, but small quantities were regularly consumed. The amount of animal material consumed (ants, birds, beetles, and grasshoppers) was less than 1% of the total diet. The habit of storing food is not well developed in these rats, but small quantities of food are usually found at each house. Drinking water is not required because of the high water content in their choice of foods.

The breeding season is restricted largely to the period from January to September. At least two and possibly three or more litters of two or three young each may be reared during this period. The period of gestation is approximately 38 days. At birth the young are helpless, weigh about 11 g, and are about twice the size of newborn house rats. As is the case with other woodrats and many related species of mice, the young ones have specially developed front teeth that permit them to grasp the nipples of the mother and to be dragged along behind her, skidding and bouncing along on their backs, when she leaves the nest. They grow rapidly; the ears open on the 13th to 15th day, the eyes open on the 15th to 19th day, and they are weaned when 62-72 days old. When about 6 months old they are almost indistinguishable from their elders.

The spiny fortress in which the house is located, coupled with the nocturnal habits of the rats, makes them relatively safe from most predators. Owls catch a few individuals, as do coyotes, bobcats, ringtails, and weasels but their chief natural enemies appear to be the large desert gopher snake and the rattlesnake, both of which can enter the houses of the rats with impunity.

Photo credit: R.D. Porter.