Meadow voles (Microtus pennsylvanicus) are common small mammals found across North America. These adaptable rodents play a role in various ecosystems, often unnoticed due to their secretive nature.
Identifying Meadow Voles
Meadow voles have a stout, cylindrical body with short legs and a stocky build, measuring 130 to 185 millimeters (5.1 to 7.3 inches) in total length, including their short tail. Adults typically weigh around 44 grams (1.6 ounces). Their fur is dark to grayish-brown on top, with lighter shades of white, gray, or grayish-buff underneath. They have small eyes, a blunt nose, and ears nearly concealed by dense fur, giving them a compact appearance.
Distinguishing voles from other small rodents like mice and shrews involves specific physical traits. Voles have shorter tails, about one-third of their body length, and a more robust body compared to mice, which have longer tails and more slender builds, plus larger eyes and ears. Shrews have pointed snouts and often smaller, less visible eyes, differing from the vole’s rounded face.
Life and Habits
Meadow voles prefer habitats with dense ground cover, thriving in grassy fields, meadows, open woodlands, and moist environments like marshy grasslands. They generally avoid thick forests but can be found in riparian zones near water. Their diet is primarily herbivorous, consisting of grasses, sedges, roots, and seeds. They also consume clover, alfalfa, and the bark of young trees, occasionally supplementing their diet with insects. These mammals can consume up to 60% of their body weight daily.
They construct intricate networks of surface runways through dense vegetation that serve as protected pathways. These runways, often marked with feces and food remnants, connect shallow underground burrows where they build nests from dried grasses and plant materials. Meadow voles are active year-round, day and night, though activity patterns shift to more diurnal in winter and nocturnal in summer. They often live in colonies; females typically defend individual territories, while males have overlapping home ranges.
The reproductive cycle of meadow voles is rapid. Females can produce multiple litters annually, with a gestation period averaging 21 days. Litter sizes typically range from four to six young, though they can have up to 11 offspring. The young are born altricial (hairless with closed eyes and ears) and are weaned quickly, usually within 12 to 14 days. Females can reach sexual maturity as early as three weeks, while males mature around five to six weeks.
Ecological Role and Human Interaction
Meadow voles play an important role within their ecosystems, primarily serving as a widespread food source for a diverse array of predators. Their consumption by animals such as hawks, owls, foxes, weasels, snakes, coyotes, and domestic cats helps sustain these predator populations. Beyond their role as prey, their burrowing activities aerate the soil, benefiting plant growth and nutrient cycling. These actions also contribute to plant succession in open habitats.
Their feeding and burrowing habits can impact vegetation by grazing on grasses and other herbaceous plants. While generally harmless to humans, meadow voles can occasionally become agricultural or garden pests. They can damage crops, ornamental plants, and young trees by feeding on roots, stems, seeds, and stripping bark, especially during winter when food is scarce and they operate under snow cover. Although they pose a low health risk to humans due to infrequent direct contact, they can carry certain disease organisms, including plague and tularemia.