vole

Vole
The bank vole (Myodes glareolus) lives in woodland areas in Europe and Asia.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Cricetidae
Subfamily:	Arvicolinae in part
Genera
See text.

A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars (high-crowned and with angular cusps instead of low-crowned and with rounded cusps). There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America. Vole species form the subfamily Arvicolinae with the lemmings and the muskrats.

Description

Voles are small rodents that grow to 3-9 inches, depending on the species. They can have 5–10 litters per year. Gestation lasts for 3 weeks and the young voles reach sexual maturity in a month. As a result of this exponential growth, vole populations can grow very large within a very short period of time. Since litters average 5–10 young, a single pregnant vole in a yard can result in a hundred or more active voles in less than a year.

Voles are commonly mistaken for other small animals. Moles, gophers, mice, rats and even shrews have similar characteristics and behavioral tendencies. Since voles will commonly use burrows with many exit holes, they can be mistaken for gophers or some kind of ground squirrel.

They will readily thrive on small plants. Like shrews they will eat dead animals and like mice or rats, they can live on almost any nut or fruit. Additionally, voles will target plants more than most other small animals. It is here where their presence is mostly evident. Voles will readily girdle small trees and ground cover much like a porcupine. This girdling can easily kill young plants and is not healthy for trees or other shrubs.

Voles will often eat succulent root systems and will burrow under plants or ground cover they are particularly fond of and eat away until the plant is dead. Bulbs in the ground are another favorite target for voles; their excellent burrowing and tunnelling gives them access to sensitive areas without clear or early warning. The presence of large numbers of voles is often only identifiable after they have destroyed a number of plants.^[1] However, voles, like other burrowing rodents, also play beneficial roles including dispersing nutrients throughout the upper soil layers.^[2]

Predators

Many predators such as martens, raccoons, owls, hawks, falcons, coyotes, foxes, snakes, the red tailed hawk, weasels, cats and dogs eat voles. Vole bones are often found in the pellets of the short-eared owl as well as the northern spotted owl, the Saw-whet Owl, the barn Owl, the Great Gray Owl and the Northern Pygmy Owl.^{[citation needed]}

Lifespan

The average life of the smaller vole species is 3–6 months. These voles rarely live longer than 12 months. Larger species, such as the european water vole, live longer and usually die during their second, or rarely their third, winter. It is estimated that as many as 88% of voles die within the first month of life.^[3]

Genetics and sexual behavior

The prairie vole is a notable animal model for its monogamous sexual fidelity, since the male is usually faithful to the female, and shares in the raising of pups. (The woodland vole is also usually monogamous.) Another species from the same genus, the meadow vole, has promiscuously mating males, and scientists have changed adult male meadow voles' behavior to resemble that of prairie voles in experiments in which a single gene was introduced into the brain via a virus.^[4]

The behavior is influenced by the number of repetitions of a particular string of microsatellite DNA, and the same DNA sequence is found in humans. Male prairie voles with the longest DNA strings spend more time with their mates and pups than male prairie voles with shorter strings.^[5] However, other scientists have disputed the gene's relationship to monogamy, and cast doubt on whether the human version plays an analogous role.^[6] Physiologically, pair-bonding behavior has been shown to be tied up with vasopressin, dopamine, and oxytocin, with the genetic influence apparently arising via the number receptors for these substances in the brain; the pair-bonding behavior has also been shown in experiments to be strongly modifiable by administering some of these substances directly.

Voles exhibit complex genetic structures^[vague] with much variation, and appear to be evolving rapidly when compared with other vertebrates^{[citation needed]}. For this reason, they can be useful to archaeologists for dating strata, in a method referred to as the "vole clock".^{[citation needed]}

Voles have a number of unusual chromosomal traits. Species have been found with anywhere from 17–64 chromosomes, and in some species males and females have different chromosome numbers. Female voles have been found with chromosomes from both sexes, and in one species the sex chromosomes contain 20% of the genome. All of these variations result in very little physical aberration: most vole species are virtually indistinguishable.^[7]

Classification

• Order Rodentia
  • Superfamily Muroidea
    • Family Cricetidae
      • Subfamily Arvicolinae (in part)
        • Tribe Arvicolini
          • Genus Arvicola - water voles
          • Genus Blanfordimys - Afghan vole and Bucharian vole
          • Genus Chionomys - snow voles
          • Genus Lasiopodomys
          • Genus Lemmiscus - sagebrush vole
          • Genus Microtus - voles
          • Genus Neodon - mountain voles
          • Genus Phaiomys
          • Genus Proedromys - Duke of Bedford's vole
          • Genus Volemys
        • Tribe Ellobiusini - mole voles
          • Genus Ellobius - mole voles
        • Tribe Lagurini
          • Genus Lagurus - steppe vole (also called steppe lemming)
        • Tribe Myodini
          • Genus Alticola - voles from Central Asia
          • Genus Caryomys
          • Genus Eothenomys - voles from East Asia
          • Genus Hyperacrius - voles from Pakistan
          • Genus Myodes - red-backed voles
        • Tribe Pliomyini
          • Genus Dinaromys - voles from the Dinaric Alps
        • incertae sedis
          • Genus Arborimus - tree voles
          • Genus Phenacomys - heather voles

References

External links

• Voles.com, pictures and information about voles and vole related topics
• Pest control article
• National Geographic video.