Peromyscus polionotusoldfield mouse

Geographic Range

Peromyscus polionotus occurs in the southeastern United States. Populations in the continental United States have been found scattered throughout parts of Mississippi, Tennessee, North Carolina, South Carolina, and south to Florida (Whitaker and Hamilton, 1998; Wilson and Ruff, 1999). This species of deer mouse also inhabits coastal islands off the southeastern sea board (Nowak 1999). (Nowak, 1999; Whitaker Jr. and Hamilton Jr., 1998; Wilson and Ruff, 1999)


Oldfield mice inhabit diverse environments. These mice typically occupy early successional habitats such as abandoned fields, beach dunes, and scrub habitats (Wilson and Ruff, 1999). They dig underground nest cavities which lie 0.3 to 0.9 meters below the surface. There is a leading and an escaping tunnel. A mound of soil or sand marks the entrance of the leading tunnel. (Wilson and Ruff, 1999)

Physical Description

Adult females are slightly larger than adult males (Wilson and Ruff 1999). Total length ranges from 110 to 150 millimeters with the average tail length ranging from 40 to 60 millimeters. Weight varies between 10 and 15 grams (Wilson and Ruff 1999). Peromyscus polionotus has several distinguishing characteristics. This species is smaller in size and has a smaller skull compared to other species in th genus Peromyscus. The white and brown colored tail, with a white underside, are two identifiable characteristics (Whitaker and Hamilton, 1998). (Whitaker Jr. and Hamilton Jr., 1998; Wilson and Ruff, 1999)

Distinct local color variation is found among the subspecies. For example, individuals inhabiting the beach tend to have less pigmented hair than individuals of an inland population (Wilson and Ruff 1999). This pale coloration may help beach populations blend into the sandy environment, thus avoiding predation. (Wilson and Ruff, 1999)

  • Sexual Dimorphism
  • female larger
  • Range mass
    10 to 15 g
    0.35 to 0.53 oz
  • Range length
    110 to 150 mm
    4.33 to 5.91 in
  • Average basal metabolic rate
    0.12 W


These mice are monogamous, with the breeding pair remaining together for a period of time. (Nowak, 1999; Wilson and Ruff, 1999)

Breeding of Peromyscus polionotus occurs throughout the year. There is a decline in breeding activity during the summer (Wilson and Ruff 1999). Gestation is 24 days in length but may be a few days longer if a previous litter is still nursing (Whitaker and Hamilton, 1998). Litter size ranges between three and four individuals. The average age for the first estrus cycle in a female is 29.6 days (Nowak, 1999). (Nowak, 1999; Whitaker Jr. and Hamilton Jr., 1998; Wilson and Ruff, 1999)

  • Breeding interval
    Females can have multiple litters in a year.
  • Breeding season
    Breeding occurs year-round.
  • Range number of offspring
    3 to 4
  • Average number of offspring
  • Average gestation period
    24 days
  • Average gestation period
    24 days
  • Range weaning age
    20 to 25 days
  • Average age at sexual or reproductive maturity (female)
    30 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    28 days
  • Average age at sexual or reproductive maturity (male)
    30 days

At birth, the young are helpless, weighing only 6 to 7 grams. They are pink in color and hairless with the exception of vibrissae around the nose. The eyes do not open until the thirteenth or fourteenth day of life. The litter is weaned around 20-25 days after birth. Above-ground activity occurs after weaning. (Wilson and Ruff, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female


Oldfield mice probably live for no longer than about 18 months in the wild. (Wilson and Ruff, 1999)

  • Typical lifespan
    Status: wild
    18 (high) months
  • Average lifespan
    Status: captivity
    5.5 years


Oldfield mice are primarily nocturnal. Highest levels of activity have been recorded on moonless or cloudy evenings. These mice are also hoarders and excellent diggers. Stashes of seeds have been found underground in their burrowed nests. Oldfield mice construct and use extensive burrows. They are most likely restricted to sandy and loamy soils throughout their range because of their reliance on tunneling. (Wilson and Ruff, 1999)

Home Range

Oldfield mice probably occupy the same general area throughout their lives and may defend small territories. (Wilson and Ruff, 1999)

Communication and Perception

Like other Peromyscus species, oldfield mice have keen vision, hearing, and tactile sensation. They use chemical cues extensively in communication.

Food Habits

Oldfield mice are granivorous, feeding on the seeds of grasses and herbs. They store food in underground caches (Wilson and Ruff, 1999). They will also consume arthropods, insect parts have been found in nests (Gentry and Smith, 1968). (Gentry and Smith, 1968; Wilson and Ruff, 1999)

  • Animal Foods
  • insects
  • Plant Foods
  • seeds, grains, and nuts


Oldfield mice are preyed upon by many small predators, such as raptors, owls, snakes, weasels, foxes, and cats (Whitaker and Hamilton, 1998). They escape predation by seeking refuge in their burrows and by being active primarily at night. (Whitaker Jr. and Hamilton Jr., 1998)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Oldfield mice are an important prey base for small predators in the areas in which they live. They may also play an important role in influencing seed survivorship of the plant communities in which they occur. The following parasites have been found in individuals living in Florida: nematodes- six species, trematodes- one species, acanthocephalans- one species, and fleas- two species (Whitaker and Hamilton 1998). (Whitaker Jr. and Hamilton Jr., 1998)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Oldfield mice are excellent models for genetic research and have been used extensively to study variation in pigment controlling genes.

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

It has been reported that Peromyscus polionotus can be a pest when it digs up the seeds of local gardeners for consumption (Whitaker and Hamilton 1998). (Whitaker Jr. and Hamilton Jr., 1998)

  • Negative Impacts
  • household pest

Conservation Status

Several subspecies of P. polionotus are on conservation lists. The status varies by subspecies. For example, on the IUCN list, some subspecies are listed as extinct while others are listed as endangered, critically endangered, or lower risk. Beach development and water recreation are just two causes for this mouse being in danger of extinction (Wilson and Ruff, 1999). A third probable danger to P. polionotus is climatic. For example, the coast along the Gulf of Mexico has been subject to hurricanes and other violent weather in the past. Swilling et. al (1998) have recorded populations of Peromyscus polionotus to be severely reduced several months after Hurricane Opal hit the Alabama coast. (Swilling Jr, et al., 1998; Wilson and Ruff, 1999)

Subspecies of oldfield mice considered endangered are: Peromyscus polionotus allophrys, Peromyscus polionotus ammobates, Peromyscus polionotus peninsularis, Peromyscus polionotus phasma, and Peromyscus polionotus trissyllepsis, all of which occur in Florida and Alabama. Peromyscus polionotus niveiventris are considered threatened, they occur in Florida. Additional subspecies recognized by the IUCN are Peromyscus polionotus leucocephalus, near threatened in Florida, and Peromyscus polionotus decoloratus, extinct from Florida.

Other Comments

Fossil evidence in the geological record dates this mouse back to the late Pleistocene epoch (Wilson and Ruff 1999). (Wilson and Ruff, 1999)


Desirae Foust (author), University of Northern Iowa, Jim Demastes (editor), University of Northern Iowa.



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


uses sound to communicate


living in landscapes dominated by human agriculture.


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

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.


uses smells or other chemicals to communicate


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.


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.


Referring to a burrowing life-style or behavior, specialized for digging or burrowing.


an animal that mainly eats seeds


An animal that eats mainly plants or parts of plants.


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).


Having one mate at a time.


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.


active during the night

scrub forest

scrub forests develop in areas that experience dry seasons.


remains in the same area


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


associates with others of its species; forms social groups.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"


living in residential areas on the outskirts of large cities or towns.


uses touch to communicate


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).


Living on the ground.


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


The term is used in the 1994 IUCN Red List of Threatened Animals to refer collectively to species categorized as Endangered (E), Vulnerable (V), Rare (R), Indeterminate (I), or Insufficiently Known (K) and in the 1996 IUCN Red List of Threatened Animals to refer collectively to species categorized as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU).

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


uses sight to communicate


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


Gentry, J., M. Smith. 1968. Food habits and burrow associates of *Peromyscus polionotus*. Journal of Mammalogy, 49: 562-565.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition VII. Baltimore and London: The Johns Hopkins University Press.

Swilling Jr, W., M. Wooten, N. Holler. 1998. Population dynamics of Alabama beach mice (*Peromyscus polionotus ammobates*) following Hurrican Opal. American Midland Naturalist, 140, no 2: 287-298.

Whitaker Jr., J., W. Hamilton Jr.. 1998. Mammals of the Eastern United States. Ithaca and London: Cornell University Press.

Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington and London: Smithsonian Institution Press.