 |
By Melissa VanderLinden
Geographic Range
Prairie voles, Microtus ochrogaster, occur from northeastern New Mexico to northern Alabama, western West Virginia, and northwest to central Alberta. (Stalling, 1990)
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. (Kurta, 1995; Stalling, 1990)
These animals are found in the following types of habitat:
temperate 
; terrestrial .
Terrestrial Biomes:
savanna or grassland .
Other:
agricultural .
Physical Description
(1.06 to 2.46 oz; avg. 1.76 oz)
(4.92 to 7.09 in; avg. 6 in)
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. (Kurta, 1995; Stalling, 1990; Stalling, 1999; University of Kansas, 2000)
Some key physical features:
endothermic ; bilateral symmetry .
Sexual dimorphism: sexes alike.
Reproduction
These animals can produce several litters per year. The maximum is about one litter every month and a half.
Breeding occurs year-round.
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. (Getz and Carter, 1996; Stalling, 1990; Stalling, 1999)
Mating systems:
monogamous ; 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. (Kurta, 1995; Stalling, 1990; Stalling, 1999)
Key reproductive features:
iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; 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. (Kurta, 1995; Stalling, 1990; Stalling, 1999)
Parental investment:
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. (Kurta, 1995; Stalling, 1990)
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. (Getz and Carter, 1996; Stalling, 1990)
Home Range
The size of individual home ranges has not been reported.
Key behaviors:
terricolous; crepuscular ; motile ; sedentary ; territorial ; social .
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. (Stalling, 1990)
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. (Kurta, 1995)
Animal Foods:
insects.
Plant Foods:
leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts.
Foraging Behaviors:
stores or caches food .
Predation
- hawks (Accipitridae)
- owls (Strigiformes)
- shrikes (Lanius)
- red foxes (Vulpes vulpes)
- coyotes (Canis latrans)
- bobcats (Lynx rufus)
- weasels (Mustela)
- snakes (Serpentes)
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. (Kurta, 1995; Stalling, 1990)
Anti-predator adaptations::
cryptic .
Ecosystem Roles
Prairie voles are important in nutrient cycling in prairie ecosystems and as prey animals for many predator species. (Kurta, 1995; Stalling, 1990)
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. (Lesnar, 1997; Stalling, 1999)
Ways that these animals might be a problem for humans:
crop pest.
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. (Stalling, 1999)
Ways that people benefit from these animals:
research and education.
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
State of Michigan List: [link]:
Endangered.
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. (Lesnar, 1997)
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. (Lesnar, 1997; Stalling, 1990)
Contributors
Nancy Shefferly (editor), Animal Diversity Web Staff.
Melissa VanderLinden (author), University of Wisconsin-Stevens Point.
Chris Yahnke (editor), University of Wisconsin Stevens Point.
