Ochrotomys nuttalli
golden mouse

Ochrotomys nuttalli lives throughout the southern United States from northern Kentucky to central Florida and from eastern Texas to the Atlantic Ocean. (Dietz et al., 1992)

Golden mice, O. nuttalli, live in thick woodlands, swampy areas, among vines, and within small trees and shrubs. These animals especially like to live where honeysuckle, greenbrier, and red cedar grow. Golden mice in the south-central region of the United States inhabit climates that are hot and wet in the summer and dry in the winter.

Their nests may be located in the trees or on the ground. Ground nests, frequently located near leaf litter, may be fabricated within sunken areas of the soil or beneath logs. Ground nests have both advantages and disadvantages. Floods or wet soil may force golden mice to leave their ground nests and relocate into the trees. However, if the ground nest is undisturbed, it can lower the risk for predation for the following reasons: the nest is well hidden, a mouse on the ground is more likely to escape a predator, and less energy is required to build a nest on the ground since the mouse doesn't have to keep running up and down a tree with nesting materials.

Golden mice have been known to remodel old bird nests into homes for themselves. Otherwise these animals create a nest 100 to 200 mm in size, from scratch using different elements, depending on what materials are locally available.

The inner lining of a nest consists of soft materials such as milkweed, cotton, feathers, or fur. A thick layer of woven fibers surrounds this fluffy layer. The protective, surface material contains leaves, grass, and bark. The nest usually has one entrance, although up to three have been noted.

Home ranges, which overlap with one another, are from 0.053ha to 0.627ha. (Dietz, 1992; Frank, 1992; Grosvenor, 1987; Nowak, 1991)

The body length of O. nuttalli ranges from 51 to 115 mm. The prehensile tail is from 50 to 97 mm in length, generally the same length as the body of the mouse to which it belongs. Golden mice receive their common name from the thick and soft golden fur that covers the upper body. However, the feet and undersides are white and its tail have a cream coloring.

Male golden mice have a baculum tipped with cartilage. Females have six mammae.

The cheek teeth of golden mice contain thick folds of enamel. As in other members of Muridae, these mice have an infraorbital foramen with a distinct keyhole shape. Neither canines nor premolars are present. Incisors are sharp and long, separated from the cheek teeth by a diastema. (Grosvenor et al., 1987; Hall, 1981; Myers, 1997; Nowak, 1993)

Ochrotomys nuttalli is mainly nocturnal and arboreal, although many live on the ground as well. Golden mice move quickly and easily. They are able to use their prehensile tails to balance while climbing trees and also to hang from branches.

Ochrotomys nuttalli is a gregarious creature. In fact, up to eight mice have been discovered sharing a nest at one time. Groups can consist of kin or unrelated individuals. The most common groups consist of mothers and their young. Many scientists speculate that living in groups conserves energy. This idea is supported by the observation that mice are found in groups more often in the winter when such grouping produces a clear cut thermoregulatory benefit.

Golden mice have a low basal metabolic rate and high conductance. When their areas become flooded, golden mice activity is significantly reduced.

Ochrotomys nuttalli in captivity has displayed submissive behavior. (Dietz et al., 1992; Frank, 1992; Grosvenor, 1987; Nowak, 1991; Rose et al., 1988)

Golden mice are granivorous, eating mostly seeds. They prefer sumac seeds, but also consume honeysuckle and other seeds as well. Sumac seeds are poor quality food because they contain tannin, which reduces the efficiency of enzymes in the mouse's digestive pathway. Studies have shown that females fed year-old seeds, which have more calories, have significantly higher mean ingestion and assimilation rates than females that eat freshly matured seeds.

Flooding is a problem for golden mice because the water causes the seeds to be unobtainable, to sprout, or to spoil. (Jewell et al., 1991; Peles et al., 1995; Rose et al., 1988)

Golden mice are presently threatened to be endangered in the state of Illinois. The Department of Zoology at Southern Illinois University is presently studying the nesting sites of this rodent. (http://dnr.state.il.us/ILDNR/OFFICES/PUBAFFRS/news/small97.html)

Ochrotomys is regarded as a subgenus of Peromyscus by some systematists. (Nowak, 1991)