Microtus pennsylvanicus

Eastern meadow vole Microtus pennsylvanicus, copyright Brian Henderson.

Belongs within: Microtus.

Voley, voley, voley
Published 23 April 2022

Over a third of all living mammal species are rodents. In cooler regions of the Northern Hemisphere, the rodent fauna is often dominated by the Microtinae, the group of mouse-like rodents including voles and lemmings. And in North America, the most widespread of all microtine species is the eastern meadow vole Microtus pennsylvanicus.

Eastern meadow vole Microtus pennsylvanicus, copyright Gilles Gonthier.

The eastern meadow vole is found over most of Canada and a large part of the northern and eastern United States, with the subspecies M. p. chihuahuensis known from Chihuahua in northern Mexico. This species is about the size of a small rat, being from 14 to 20 cm in length with about three to six centimentres of that length being tail (Reich 1981). They are generally yellowish-brown in colour with black tips on the hairs though individuals vary significantly in brightness and shade. Western populations are supposed to be lighter in coloration than eastern, and southern individuals tend to be larger than northern. As an indication of this species’ variability, Reich (1981) recognised 28 recognised subspecies.

Eastern meadow voles are primarily inhabitants of grasslands, with a preference for damper habitats, though they may also be found in woodlands. They mostly live in burrows underground, emerging to the surface to forage for food. Eastern meadow voles are generalist feeders, browsing on most available forms of low vegetation: grasses, sedges and herbs. When populations reach their peak, they may cause significant damage to woody plants by ringbarking their trunks. Individuals may seemingly be active at just about any time of day.

Eastern meadow vole in a state of danger, copyright David Allen.

Like other small rodents, meadow voles are short-lived animals with estimates of average lifespan ranging from just two or three months to ten to fourteen months (Reich 1981). Studies of movement patterns indicate that mature females generally maintain distinct, non-overlapping ranges whereas males range further and with less concern for others (Madison 1980). Mating behaviour appears generally promiscuous: males will range over the territories of multiple females and litters with mixed paternity are not uncommon (Boonstra et al. 1993). Paternal behaviour has been observed among eastern meadow voles in laboratory populations but all indications are that wild males do not remain with females after mating. Males often bear wounds indicative of intra-species conflict. These may be the result of males fighting over access to females but Madison (1980) suggested a potential alternative. Less dominant males might be more likely to attempt to approach females earlier or later in their oestrus cycle as the females are more likely to be guarded by dominant males when at their peak. While avoiding attacks from their dominant brethren, these minor males might find themselves violently rebuffed by a female who is just not yet in the mood.

After mating, gestation lasts for about three weeks, usually resulting in a litter of four to six babies. Weaning then takes place after about two weeks. Females forage far less while lactating than at other times. It might seem counter-intuitive for a female to reduce feeding when her energy demands are presumably at their peak but again Madison (1980) suggests an explanation: perhaps her energy needs are such that she simply lacks the capacity for extensive wandering. Young may potentially remain with their mother for some time after weaning but eventually they will be forced out of the parental burrow, leaving to face the wide world on their own. And when you’re the size of a vole, that’s a very wide world indeed.

Systematics of Microtus pennsylvanicus
<==Microtus pennsylvanicus (Ord 1815) [=Mus pennsylvanica]R81
|--M. p. pennsylvanicus (see below for synonymy)R81
|--M. p. acadicus Bangs 1897R81
|--M. p. admiraltiae Heller 1909R81
|--M. p. alcorni Baker 1951R81
|--M. p. aphorodemus Preble 1902R81
|--M. p. arcticus Cowan 1951R81
|--M. p. aztecus (Allen 1893) [=Arvicola (Mynomes) aztecus]HC52
|--M. p. chihuahuensis Bradley & Cockrum 1968P81
|--M. p. copelandi Youngman 1967R81
|--M. p. drummondii (Audubon & Bachman 1854) [=Arvicola drummondii; incl. M. stonei Allen 1899]R81
|--M. p. enixus Bangs 1896R81
|--M. p. finitus Anderson 1956A56
|--M. p. fontigenus Bangs 1866R81
|--M. p. funebris Dale 1940HC52
|--M. p. insperatus (Allen 1894) [=Arvicola insperatus; incl. M. pennsylvanicus wahema Bailey 1920]A56
|--M. p. kincaidi Dalquest 1941R81
|--M. p. labradorius Bailey 1898R81
|--M. p. magdalensis Youngman 1967R81
|--M. p. microcephalus (Rhoads 1894) [=Arvicola (Mynomes) microcephalus]R81
|--M. p. modestus (Baird 1858) [=Arvicola modesta]A56
|--M. p. nigrans Rhoads & Young 1897R81
|--M. p. provectus Bangs 1908R81
|--M. p. pullatus Anderson 1956A56
|--M. p. rubidus Dale 1940R81
|--M. p. shattucki Howe 1901R81
|--M. p. tananaensis Baker 1851R81
|--M. p. terraenovae (Bangs 1894) [=Arvicola terraenovae]R81
`--M. p. uligocola Anderson 1956A56

Microtus (Microtus) pennsylvanicus pennsylvanicus (Ord 1815) [incl. Arvicola alborufescens Emmons 1840, A. dekayi Audubon & Bachman 1854, A. fulva Audubon & Bachman 1841, A. hirsutis Emmons 1840, A. riparia var. longipilis Baird 1858, A. nasuta Audubon & Bachman 1841, Lemmus noveboracensis Rafinesque 1820, A. oneida DeKay 1842, A. palustris Harlan 1825, Mynomes pratensis Rafinesque 1817, A. riparius Ord 1825, A. rufescens DeKay 1842 non de Selys Longchamps 1836, A. rufidorsum Baird 1858]R81

*Type species of generic name indicated

References

[A56] Anderson, S. 1956. Subspeciation in the meadow mouse, Microtus pennsylvanicus, in Wyoming, Colorado, and adjacent areas. University of Kansas Publications, Museum of Natural History 9 (4): 85–104.

Boonstra, R., X. Xia & L. Pavone. 1993. Mating system of the meadow vole, Microtus pennsylvanicus. Behavioral Ecology 4: 83–89.

[HC52] Hall, E. R., & E. L. Cockrum. 1952. Comments on the taxonomy and geographic distribution of North American microtines. University of Kansas Publications, Museum of Natural History 5 (23): 293–312.

Madison, D. M. 1980. Space use and social structure in meadow voles, Microtus pennsylvanicus. Behavioral Ecology and Sociobiology 7: 65–71.

[R81] Reich, L. M. 1981. Microtus pennsylvanicus. Mammalian Species 159: 1–8.

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