Reithrodontomys fulvescens can be found in southeast Arizona, southwest and east Texas, east Oklahoma, southeast Kansas, southwest Missouri, west Arkansas, Louisiana, and west Mississippi (Whitaker, J.O. Jr. 1980, Davis and Schmidly 1994).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Southern Arizona, extreme southwestern New Mexico, Texas, southeastern Kansas and southwestern Missouri south through much of Mexico to southern Guatemala, El Salvador, Honduras, and western Nicaragua (Hall 1981).

This mouse resembles the house mouse but differs in its hairier tail and grooved upper incisors (Nowak 1991). The length of the tail is greater than half of the total body length (Whitaker, Jr. 1980). Ears of R. fulvescens are large. The hair on the upper body is a mixture of reddish brown and black, creating a salt and pepper effect (Hall and Kelson 1959). R. fulvescens has a tail that is much longer than its body and its under parts are white to buff. The adult plumage is brighter than that of the juvenile and adults molt once a year. Females have six mammae. A typical harvest mouse weighs about 18 grams.

Average mass: 18 g.

Length: 20 cm

Weight: 30 grams

• Terrestrial

This mouse occurs mostly in low grassy or weedy areas or along creek bottoms with tangled vines and bushes. In southern areas, R. fulvescens lives in "arid inland valleys where temperatures are high and the soil is sandy or rocky" (Hall and Kelson 1959).

Terrestrial Biomes: savanna or grassland

Comments: Favors grassy areas containing shrubs or shrubby trees. Nests usually are built 1-3 feet above the ground.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

The diet of R. fulvescens mainly consists of seeds, the green shoots of vegetation and some insect larvae. The fulvous harvest mouse seems to enjoy butterfly larvae (Grzimek 1972, Grzimek 1990).

Comments: Eats weed seeds (fall/winter), invertebrates (spring/summer) (Spencer and Cameron 1982), soft parts of green plants (Whitaker 1980).

In two studies, average home range was about 850 and 2000 sq m (see Spencer and Cameron 1988). Peak winter densities may reach 27/ha but usually average 5-10/ha (Cameron 1977). Packard (1968) reported densities of about 7.5/ha in eastern Texas.

Comments: Primarily nocturnal; peak activity around 2100 hrs (Cameron et al. 1979).

Peaks in reproduction for R. fulvescens occur in late spring and early autumn with a breeding season that extends from February all the way through to October. The gestation period is approximately twenty days with an average litter size of about three or four. Each newborn weighs about one gram. By the second week, the young are well-furred and by about nine to twelve days, the eyes are open (Davis and Schmidly 1994). At three weeks, the young leave the nest and by five weeks, they are at full size (Grzimek 1990).

Breeds year-round; peak in March, July. Litter size is 2-4. Young are weaned in 13-16 days. Probably sexually mature in 2-4 months.

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Comments: Patterns of genetic variation suggest that this species as currently defined may be represented by more than one species; further study is warranted (see Musser and Carleton, in Wilson and Reeder 2005). For a phylogenetic analysis of Reithrodontomys species based on mitochondrial DNA, see Bell et al. (2001).