Microtus pennsylvanicus
ID
- Dense, soft fur of a chestnut brown in the summer and a darker gray in the winter
- Tail is usually at least twice as long as the hind foot
- Six tubercles on the soles of the hind feet (Whitaker)
Distribution
Reproduction
- Can produce as many as 17 litters in a year
- Gestation is 20-21 days with litters ranging from 1 to 11 young
- Females can breed by 3 weeks old
- Both males and females are promiscuous (Whitaker)
Behavior
- Males will often kill babies in nests that they find unless the mother is a female with whom he has mated
- Most prolific mammal in the world
- Spend a lot of time above ground on runway trails that are maintained by the voles chewing anything that sprouts in the path
- Active both day and night, but peak activity hours are early morning and late afternoon
- Can swim, but cannot climb
- Individuals can apparently orient themselves by the sun
Food Habits
- Grasses, seeds, rootstocks, tender barks. Stores roots, tubers, leaves, and other plant parts for winter
- Eat more than their weight in food daily and need to engage in coprophagy in order to absorb adequate nutrition
Size/Life Cycle
- Average measurements: 167 mm (total length), 33-65 g (total weight) (Smithsonian)
Predators
- Almost anything, but especially weasels and house cats
Habitat
- Moist fields of dense vegetation containing grasses and sedges, low meadows, swampy pastures, fields with protecting covers of dead grasses and herbs, coastal salt meadows, and bluegrass fields