Microtus ochrogaster (Wagner)
Color photo by Barbara L. Clauson.
Description: The prairie vole is a stocky, compact-bodied rodent that can be distinguished from other members of its family by: 1) small eyes and ears inconspicuous on the relatively large head, 2) grayish to blackish-brown upperparts (more grayish in central and northwestern Kansas than in eastern Kansas) with a mixture of blackish to fulvous tips on the guard hairs giving the hairs a grizzled effect, 3) paler sides, 4) ochraceous to grayish white underparts, 5) short tail dark above and light below, and usually about twice the length of the hind foot, 6) females have six nipples, 7) four islands of dentine in the upper second molar, and 8) upper incisor teeth not grooved. Sexes are alike.
Size: Adults may attain the following dimensions: total length 137-180 mm; tail 24-45 mm; hind foot 17-23 mm; ear 10-15 mm; weight 49-71 grams.
Range and Habitat:
|Three subspecies occur in Kansas: Microtus ochrogaster haydenii in the northwest and south-central, Microtus ochrogaster ochrogaster in the eastern half, and Microtus ochrogaster taylori in the southwest. Recent work indicates that all prairie voles in Kansas should probably be assigned to the subspecies M. o. haydenii (Choate and Williams, 1978). The prairie vole is generally distributed in dry to mesic prairie communities with scant to thick overhead protection, but occupies drier areas than the meadow vole. Shrubby areas and forest borders also are inhabited.|
Reproduction: The prairie vole breeds throughout the year (three or four litters) except during the hottest, driest summers, or severe winter. After a gestation period of 21 days, one to seven (usually three or four) hairless young are born with both eyes and ears closed. Their eyes and ears open in about eight days, and in two or three weeks they are weaned. Moult to subadult pelage begins after three weeks of age, followed by moult into a lighter, grayer adult pelage at about eight weeks. Females are capable of breeding 30 days after birth, and males at 35 days, when both are approximately two-thirds the adults size.
Habits: The prairie vole is the most common microtine in Kansas. Throughout the year it is active mainly at night, but sometimes by day as well,. It spends considerable time in well-defined runways which it makes and maintains in grass. These runways are approximately 50 mm wide; some are relatively deep and bare while others are faintly imprinted as trampled grass and debris on the ground. the runway system leads to holes that go steeply underground to nests and resting chambers. The underground nest (200 x 130 x 110 mm) made of grass stems and finer lining is placed 250 mm or more deep. Surface runways and underground tunnels may be shared by other species of mammals. Voles move along runways by creeping or by darting. Active runways are recognized by fresh grass clippings and fecal droppings. Foraging areas with ill-defined trails occur at the edge of the runway system. The main runways are seldom exposed except where they cross large animal trails or sparse grass cover. Populations of the prairie vole fluctuate from 200 per acre to practically none; their changes in density are not as regular or extreme as those exhibited by the meadow vole.
Food: Food consists of soft basal segments of grasses, some tubers and roots, seeds and , rarely, animal food. Vegetation is eaten on the spot or carried below ground. This vole stores greater quantities than does the meadow vole, and stored food reflects the kinds of common food available. In winter they eat bark of woody plants.
Remarks: Hawks, owls, shrews, skunks, foxes, coyotes, and bobcats are common predators of prairie voles. Longevity of this rodent is generally less than a year, but potentially it can live three or four years.
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