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Ochrotomys nuttalligolden mouse

By Deanna Riseman

Geographic Range

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)

Habitat

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)

Physical Description

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)

  • Range mass
    15 to 30 g
    0.53 to 1.06 oz
  • Range length
    51 to 115 mm
    2.01 to 4.53 in
  • Average basal metabolic rate
    0.151 W
    AnAge

Reproduction

Golden mice reproduce all year long. However, the reproductive season varies geographically. The majority of O. nuttalli reproduce from September to spring in Texas but from March to October in Kentucky and Tennessee. Golden mice in captivity tend to reproduce most frequently during the early spring and late summer. Because the gestation period is only about 30 days, females can produce many litters in one year. Captive mothers have been known to produce up to seventeen litters in an eighteen month period. A litter of golden mice typically consists of two or three young, but ranges from one to four. Aside from the mother, all other adults leave the nest when the litter is born. (Grosvenor et al., 1987; Nowak, 1991; Rose et al., 1988)

  • Breeding interval
    These mice are capable of breeding monthly, producing litters up to twelve times per year.
  • Breeding season
    The breeding season varies geographically.
  • Range number of offspring
    1 to 4
  • Average number of offspring
    2.7
    AnAge
  • Average gestation period
    30 days
  • Average gestation period
    30 days
    AnAge

Lifespan/Longevity

Behavior

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)

Communication and Perception

Food Habits

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)

  • Plant Foods
  • seeds, grains, and nuts

Conservation Status

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)

Other Comments

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

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Deanna Riseman (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Dietz, B.A. and G.W. Barrett. 1992. Nesting Behavior of Ochrotomys Nuttalli Under Experimental Conditions. Journal of Mammology. 73(3): 577-581.

Frank, P.A. and J.N. Layne. 1992. Nests and Daytime Refugia of Cotton Mice (Peromyscus gossypinus) and Golden Mice (Ochrotomys nuttalli) in South-central Florida. The American Midland Naturalist. 127(1): 21-30.

Grosvenor, G.M., O.R. Anderson, and R.L. Breeden. 1987. Wild Animals of North America. National Geographic Society: Washington D.C.

Hall, E.R. 1981. Mammals of North America. John Wiley & Sons: New York.

Illinois Endangered Species Protection Board. 1994. State of Illinois Endangered and Threatened Mammals. http://www.inhs.uiuc.edu/main/TnE.mammalte.html

Myers, P. 1997. Animal Diversity Web. http://www.oit.itd.umich.edu/projects/ADW/

Nowak, R.M. 1991. Walker's Mammals of the World. Fifth Edition, vol. 2. Johns Hopkins University Press: Baltimore.

Rose, R.K. and J.W. Walke. 1988. Seasonal Use of Nest Boxes by Peromyscus and Ochrotomys in the Dismal Swamp of Virginia. The American Midland Naturalist. 120(2): 258-265.

Wildlife Preservation Fund. 1997. 22 Small Projects Funded by Wildlife Preservation Fund. http://dnr.state.il.us/ILDNR/OFFICES/PUBAFFRS/news/small97.html

Jewell, M., M. Anderson, G. Barrett. 1991. Bioenergetics of the Golden Mouse on Experimental Sumac Seed Diets. The American Midland Naturalist, 125: 360-364.

Peles, J., C. Williams, G. Barrett. 1995. Bioenergetics of Golden Mice: The Importance of Food Quality. The American Midland Naturalist, 133: 373-376.

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