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gray-tailed vole

Microtus canicaudus

What do they look like?

Gray-tailed voles look similar to their relatives, montane voles, except their back is more yellowish, their tail is grayer and their fur is overall less grizzled. They are also similar to creeping voles; however, gray-tailed voles can be twice their size, at over 50 grams and 145 millimeters in length. Their underbelly is grayish-white, their feet are gray and their tail is gray beneath and brownish above. In the summer, their fur is light yellow-brown or yellow-gray, whereas in the winter, their fur has black tipped hairs. Juveniles are gray to grayish-brown, their feet are gray and their tail is gray with a black stripe. (Hsu and Johnson, 1970; Verts and Carraway, 1987)

  • Sexual Dimorphism
  • male larger
  • Average length
    145 mm
    5.71 in

Where do they live?

Gray-tailed voles (Microtus canicaudus) are found in the northeastern United States. They prefer low elevations throughout Willamette Valley in Oregon and areas north of the Columbia River in Clark County, Washington. (Gordon, et al., 1998; Hsu and Johnson, 1970; Verts and Carraway, 1987)

What kind of habitat do they need?

Gray-tailed voles are found in farm lands at low elevations. During the winter, their populations become smaller and smaller populations are often found in fragmented habitats. Gray-tailed voles dig tunnels and burrows 15 to 30 cm below the ground, although they sometimes use burrows made by other species. They use agricultural fields to find food and to hide from predators. (Edge, et al., 1995; Gordon, et al., 1998; Robbins, 1983; Verts and Carraway, 1987)

How do they reproduce?

The mating system used by gray-tailed voles is not known. Males have relatively small testes, which may mean that they are monogamous. However, males keep a larger home range and they are sexually dimorphic, as males are larger than females, both of which may mean they are polygynous. In this species, both females and males are territorial. Relatives of the opposite sex do not keep overlapping home ranges, which helps them avoid inbreeding. Voles also have hip glands that excrete oils used for communication in dominance, recognizing others and marking territory. These glands become much more functional during the breeding season. (Gordon, et al., 1998; Wolff, et al., 1994)

In captivity, females as young as 18 days, who weigh as little as 12.5 grams, are capable of mating and producing offspring. However, although litter sizes were larger, offspring were smaller and less likely to survive than offspring born to a 28-day-old mother. Litter sizes decrease based on the age at which females first mated. Offspring born into large litters usually have a lower birth weight. In the wild, the average litter size is 4.4 young. They breed from March through December, with a 21 to 23 day gestation period. Gray-tailed voles are able to interbreed with montane voles, however, their litters are often small and their offspring generally have a lower survival rate. (Verts and Carraway, 1987; Wolff, et al., 1994)

  • How often does reproduction occur?
    The breeding interval of gray-tailed voles is not known.
  • Breeding season
    Gray-tailed voles mate from March to December.
  • Average number of offspring
  • Range gestation period
    21 to 23 days
  • Average gestation period
    21 days
  • Range age at sexual or reproductive maturity (female)
    18 (low) days
  • Average age at sexual or reproductive maturity (female)
    28 days

There is currently very little information available about the parental investment of gray-tailed voles. However, the parental behavior of closely related prairie voles (Microtus ochrogaster) has been studied. In that species, both males and females participate in parental care, although females may limit male participation. It is not known whether gray-tailed voles show similar behavior patterns. (McGuire, et al., 2003)

How long do they live?

The lifespan of gray-tailed voles has not been reported. However, the captive lifespan of other members of genus Microtus has been reported. For instance, woodland voles (Microtus pinetorum) have a captive lifespan of 3.8 years. Likewise, field voles (Microtus agrestis) and common voles (Microtus arvalis) have a known captive lifespan of up to 4.8 years. Prairie voles (Microtus ochrogaster) have the longest known captive lifespan within the genus at 5.3 years. (Tacutu, et al., 2013)

How do they behave?

Gray-tailed voles make extensive underground runways and burrows and sometimes use the burrows of other species. These burrows are constructed 15 to 30 cm below the ground surface and range in size from 8 to 15 cm long by 3 to 5 cm wide. Nests are built underground or above ground under boards, bales and debris scattered in fields. Heavy rains often flood fields for several days at a time in the winter, so even though air trapped in nest cavities allows them to continue to live inside the burrows; they may need to swim through flooded tunnels to reach their nest. Gray-tailed voles can interbreed with other vole species, although hybrid litters are smaller and have fewer surviving offspring, so interbreeding is avoided among these species. (Boyd and Blaustein, 1985; Gordon, et al., 1998; Robbins, 1983; Verts and Carraway, 1987; Wolff, et al., 1994)

Home Range

Both males and females hold territories, but male territories are larger and overlap with many female territories. Gray-tailed voles are able to recognize other members of their species based on how familiar they are with others. How they develop this recognition is unknown, but it may have to do with oils secreted from their hip glands. How familiar gray-tailed voles are with each other changes their use of space and mating behavior. Gray-tailed voles possess many behavioral traits to avoid inbreeding, the home ranges of opposite sex relatives do not overlap. Also, individuals that are familiar with each other produce fewer litters than unfamiliar individuals. (Wolff, et al., 1994)

How do they communicate with each other?

Not much is known about communication among gray-tailed voles. These animals likely communicate using oils secreted from their hip glands, which are thought to help them establish dominance, recognize others and mark their territory. These glands are most functional during the breeding season. The ability to recognize kin also helps them avoid inbreeding, however, their method of recognizing relatives is not known. (Boyd and Blaustein, 1985; Wolff, et al., 1994)

What do they eat?

Gray-tailed voles are primarily herbivorous. They are found almost exclusively in agricultural lands, especially grasses grown for seed, small grains and pastures of legumes and grasses. They commonly inhabit forage crops with abundant food and cover. While their specific diet is not well known, it includes grasses, clovers, wild onions and false dandelions. In captivity, they are generally fed white clovers, apples, bluegrasses and ryegrasses. They may also eat some invertebrates, although studies of this are inconclusive. (Edge, et al., 1995; Schauber, et al., 1997; Verts and Carraway, 1987)

  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts
  • flowers

What eats them and how do they avoid being eaten?

Gray-tailed voles have countershaded fur, making them more difficult to hunt. They also avoid predators by building underground tunnels and by hiding in the dense cover provided by agricultural fields. Some common predators of this species include owls (Tytonidae, Strigidae), hawks (Falconidae), foxes (Vulpes vulpes, Urocyon cinereoargenteus), skunks (Mephitis mephitis) and domestic and feral cats (Felis catus). These are common predators to many other vole species as well. (Robbins, 1983; Verts and Carraway, 1987)

What roles do they have in the ecosystem?

Gray-tailed shrews are often associated with many other small mammal species including vagrant shrews (Sorex vagrans), townsend moles (Scapanus townsendii), brush rabbits (Sylvilagus bachmani), eastern cottontails (Sylvilagus floridanus), California ground squirrels (Spermophilus beecheyi), camas pocket gophers (Thomomys bulbivorus), deer mice (Peromyscus maniculatus), dusky-footed woodrats (Neotoma fuscipes), townsend voles (Microtus townsendii), creeping voles (Microtus oregoni), Pacific jumping mice (Zapus trinotatus), long-tailed weasels (Mustela frenata) and striped skunks (Mephitis mephitis). They also host several species of fleas. Gray-tailed voles use the burrows of other species, or dig their own burrows, which can be used by other species. (Robbins, 1983; Verts and Carraway, 1987)

  • Ecosystem Impact
  • disperses seeds
  • creates habitat
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

The only known negative economic effect of gray-tailed voles is the minor damage they cause to some agricultural crops. (Edge, et al., 1995)

  • Ways that these animals might be a problem for humans
  • crop pest

How do they interact with us?

Gray-tailed voles provide little positive economic impacts, outside of research. Livestock found in their range often have nutrient and vitamin deficiencies, so they have been used as test subjects studying nutrient restrictions. (Verts and Carraway, 1987)

  • Ways that people benefit from these animals:
  • research and education

Are they endangered?

Gray-tailed voles have a stable population, although human activities such as mowing and the use of pesticides have reduced their population and survival. Overall, though, they are thought to have benefited due to human farming practices. (Edge, et al., 1995; Gordon, et al., 1998; Schauber, et al., 1997; Wang, et al., 2001)


Courtney Dibble (author), Northern Michigan University, John Bruggink (editor), Northern Michigan University, Leila Siciliano Martina (editor), Animal Diversity Web Staff.


Boyd, S., A. Blaustein. 1985. Familiarity and Inbreeding Avoidance in the Gray-Tailed Vole (Microtus canicaudus). Journal of Mammalogy, 66/2: 348-352.

Dalton, C. 2000. Effects of Female Kin Groups on Reproduction and Demography in the Gray-Tailed Vole, Microtus canicaudus. Oikos, 90/1: 153-159.

Edge, D., J. Wolff, R. Carey. 1995. Density-Dependent Responses of Gray-Tailed Voles to Mowing. The Journal of Wildlife Management, 59/2: 245-251.

Gordon, D., D. Lattier, R. Salbiger, J. Torsella, J. Wolff, K. Smith. 1998. Determination of Genetic Diversity and Paternity in the Gray-Tailed Vole (Microtus canicaudus) by RAPD-PCR. Journal of Mammalogy, 79/2: 604-611.

Hsu, T., M. Johnson. 1970. Cytological Distinction between Microtus montanus and Microtus canicaudus. Journal of Mammalogy, 51/4: 824-826.

McGuire, B., E. Henyey, E. McCue, W. Bemes. 2003. Parental behavior at parturition in prairie voles (Microtus ochrogaster). Journal of Mammalogy, 84:2: 513-523.

Robbins, R. 1983. Seasonal Dynamics of Fleas Associated with the Gray-Tailed Vole, Microtus canicaudus Miller, in Western Oregon. Journal of the New York Entomological Society, 91/4: 348-354.

Schauber, E., D. Edge, J. Wolff. 1997. Insecticide Effects on Small Mammals: Influence of Vegetation Structure and Diet. Ecological Applications, 7/1: 143-157.

Tacutu, R., T. Craig, A. Budovsky, D. Wuttke, G. Lehmann, D. Taranukha, J. Costa, V. Fraifeld, J. de Magalhaes. 2013. "The Animal Aging and Longevity Database" (On-line). Human Aging Genomics Resources: Integrated Databases and Tools for the Biology and Genetics of Aging. Accessed October 11, 2013 at

Verts, B., L. Carraway. 1987. Microtus canicaudus. Mammalian Species, 267: 1-4.

Wang, G., D. Edge, J. Wolff. 2001. Rainfall and Guthion 2S Interactions Affect Gray-Tailed Vole Demography. Ecological Applications, 11/3: 928-933.

Wolff, J., D. Edge, R. Bentley. 1994. Reproductive and Behavioral Biology of the Gray-Tailed Vole. Journal of Mammalogy, 75/4: 873-879.

University of Michigan Museum of ZoologyNational Science Foundation

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Dibble, C. 2013. "Microtus canicaudus" (On-line), Animal Diversity Web. Accessed July 23, 2014 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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