Microtus ochrogaster

Geographic Range

Prairie voles, Microtus ochrogaster , occur from northeastern New Mexico to northern Alabama, western West Virginia, and northwest to central Alberta.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Prairie voles are common in prairies, ungrazed pastures, fallow fields, weedy areas, road right-of-ways, and sometimes in soybean or alfalfa fields. If meadow voles occur in the same area, prairie voles occupy the areas with shorter, drier, and more varied vegetation.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland

• Other Habitat Features
• agricultural agricultural

Physical Description

Microtus ochrogaster maintains uniform coloration throughout the year. It has dark brown to black hair tipped with black or brownish-yellow. This gives a grizzled effect to most of the pelage. The ventrum is light tan. The tail is bicolored. Occasionally, color variants with yellow, black, albino or spotted fur may be found.

Prairie voles have five plantar tubercles on the hind feet and females have three pairs of mammary glands. The third lower molar has no closed triangles and three transverse loops. The third upper molar has two closed triangles.

Adults have a total length of 125 to 180 mm, tail length of 25 to 45 mm, hind foot length of 17 to 23 mm, ear length of 10 to 15 mm, and weight between 30 and 70 grams. There is no significant sexual dimorphism in size or coloration.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Mating systems in prairie voles vary with season, food availability, and communal social structure. Some male-female pairs are monogamous while other males and females are likely to mate with multiple partners.

• Mating System
• monogamous monogamous
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Prairie voles breed throughout the year except during severe winters and summers. The highest levels of reproductive activity occur between May and October, and the lowest levels in December and January.

Gestation lasts 21 days, after which 3 or 4 hairless young are born. Young are altricial at birth, with both eyes and ears closed. Maternal age, size, and time of year have an effect on litter size.

Young develop rapidly. Within 5 days of birth they are able to crawl. They consume solid foods by the age of 12 days. Weaning occurs at 2 to 3 weeks. Young enter their first molt at about 24 days of age.

Females mature at 30 to 40 days and males at 35 to 45 days. Adult size is reached withing 2 months of birth. Young are independent shortly after weaning.

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

Both males and females care for the young, which are born naked and helpless in a grass-lined nest. The young average 3 grams at birth. Fur appears on the young by the second day, they can crawl by 5 days, begin eating solid food at 12 days, and are weaned between 2 and 3 weeks of age. The young begin to molt into their adult pelage by 24 days and reach their adult size within 2 months of birth.

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

Lifespan/Longevity

Average longevity is less than 1 year, but prairie voles may live up to 3 years in captivity.

Behavior

Microtus ochrogaster is crepuscular, though activity periods shift with the seasons. Daytime activity increases in the winter and decreases in summer. Prairie voles are found in three kinds of social arrangements: as a mated pair, as single females, and as small communal groups. The distribution of these social arrangements in prairie vole populations varies seasonally, with a larger proportion of male-female pairs during the warm months of the year and more communal behavior in the cold months of the year.

• Key Behaviors
• terricolous
• crepuscular crepuscular
• motile motile
• sedentary sedentary
• territorial territorial
• social social

Home Range

The size of individual home ranges has not been reported.

Communication and Perception

As is true of most rodents, communication is likely to involve a number of different mechanisms. Although not specifically reported for these animals, vocalizations are common in rodents, as are scent cues. Tactile communication is important between mates and within a nest containing young. Further, different body postures seem to play some role in defensive interactions within the species.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Prairie voles are herbivorous. Food items include soft basal segments of grasses, tubers and roots, and seeds, which may be stored below ground. Insects are eaten when they are available. In winter, prairie voles sometimes eat the bark of woody vegetation.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Animal Foods
• insects

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts

• Foraging Behavior
• stores or caches food stores or caches food

Predation

Prairie voles use an extensive runway system comprized of grass tunnels that helps to hide them from predators. Prairie voles are preyed upon by a wide variety of small to medium-sized predators. They are important as a prey base for raptors, owls, snakes, weasels, foxes, and bobcats.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Prairie voles are important in nutrient cycling in prairie ecosystems and as prey animals for many predator species.

Economic Importance for Humans: Positive

Prairie voles are important parts of the prairie ecosystems in which they live. They have also been used in research for many decades.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

In places near agricultural fields or gardens, prairie voles may be considered pests. Prairie voles cause damage to trees by stem injury, with pines most commonly affected.

• Negative Impacts
• crop pest

Conservation Status

Loss of native prairies is causing a decline in prairie vole populations in parts of the upper Midwest. They are listed as endangered in the state of Michigan.

Other Comments

Microtus is a greek word for "small ear" and ochrogaster is Greek for "yellow belly". Prairie voles undergo a two to four year population cycle where populations increase and decrease dramatically in that cycle.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Melissa VanderLinden (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

References

Getz, L., C. Carter. 1996. Prairie vole partnerships. American Scientist , 84: 56-62.

Kurta, A. 1995. Mammals of the Great Lakes Region . Ann Arbor, Michigan: The University of Michigan Press.

Lesnar, D. 1997. "Prairie Vole (*Microtus ochrogaster*)" (On-line). Accessed 28 November 2001 at http://www.northern.edu/natsource/MAMMALS/Prairi1.htm .

Stalling, D. 1990. *Microtus ochrogaster*. Mammalian Species , 355: 1-9.

Stalling, D. 1999. Prairie vole| Microtus ochrogaster . The Smithsonian Book of North American Mammals . Washington, D.C.: The Smithsonian Institution Press in Association with the American Society of Mammalogists.

University of Kansas, 2000. "*Microtus ochrogaster*" (On-line). Mammals of Kansas. Accessed 28 November 2001 at http://www.ksr.ku.edu/libres/Mammals_of_Kansas/microt-ochro.html .