Creeping vole | |
---|---|
Microtus oregoni photographed at Wind River Experimental Forest | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Rodentia |
Family: | Cricetidae |
Subfamily: | Arvicolinae |
Genus: | Microtus |
Subgenus: | Pitymys |
Species: | M. oregoni |
Binomial name | |
Microtus oregoni (Bachman, 1839) | |
Distribution of the creeping vole | |
Synonyms [3] | |
List
|
The creeping vole (Microtus oregoni), sometimes known as the Oregon meadow mouse, is a small rodent in the family Cricetidae. Ranging across the Pacific Northwest of North America, it is found in forests, grasslands, woodlands, and chaparral environments. The small-tailed, furry, brownish-gray mammal was first described in the scientific literature in 1839, from a specimen collected near the mouth of the Columbia River. The smallest vole in its range, it weighs around 19 g (11⁄16 oz). At birth, they weigh 1.6 g (1⁄16 oz), are naked, pink, unable to open their eyes, and the ear flaps completely cover the ear openings. Although not always common throughout their range, there are no major concerns for their survival as a species.
The animal was described in 1839 by John Bachman. [4] The original scientific name was Arvicola oregoni with a common name of the Oregon meadow mouse. [4] The type specimen was an older male collected November 2, 1836 near the mouth of the Columbia River in Oregon. [4] The specimen had been submitted to Bachman for review by John Kirk Townsend. [4] Subsequent authorities state that it was collected at Astoria, Oregon, which is at the mouth of the Columbia River. [5] In 1857, Baird placed Arvicola oregoni in a section Chilotus of the subgenus Arvicola of the genus Arvicola. [6] In 1874, PNAS paper, Coues reclassified Chilotus as a subgenus and refers to the animal as Arvicola (Chilotus) oregonus. [7] [8] Miller subsequently reclassified the animal in the genus Microtus and maintained the subgenus Chilotus. [9] This was the first reference to the animal under its current scientific name Microtus oregoni. [5] It was subsequently reclassified to the subgenus Mynomes, [3] though the American Society of Mammalogists lumps that subgenus's species in with subgenus Pitymys . [10]
Skull dimensions [5] | ||
---|---|---|
Minimum | Maximum | |
Basal length | 20.9 mm (0.82 in) | 23.4 mm (0.92 in) |
Nasal length | 6.7 mm (0.26 in) | 7.3 mm (0.29 in) |
Zygomatic breadth | 14 mm (0.55 in) | 14.9 mm (0.59 in) |
Mastoid breadth | 11 mm (0.43 in) | 12.6 mm (0.50 in) |
Upper molar alveolus | 5.5 mm (0.22 in) | 6.1 mm (0.24 in) |
On average, creeping voles weigh around 19 g (11⁄16 oz) with a reported range of 14.5 to 27.5 g (1⁄2 to 1 oz) [5] The average length is around 140 mm (5.5 in), with a range of around 129 to 154 mm (5.1 to 6.1 in) [5] Compared to other voles within their geographic range, they are the smallest. [5] They have smaller eye opening (around 2 mm (0.079 in) in diameter) compared to other voles that share the same geographic range (sympatric) or have adjacent ranges (parapatric). [5] There are other distinguishing features of the roots and enamel of the molar teeth that help in differentiation. [5] Unlike other voles in the range, only the creeping vole and the (much larger) water vole have five plantar tubercles on the hindfeet. [5]
They are Pentadactyl, although the pollex is reduced in size and lack a claw. [5] They walk with their feet planted firmly on the ground (plantigrade locomotion). [5] The foot pads have a moderate amount of fur. [5]
The fur markings are plumbeous to a dark brown or black. [5] There are sometimes yellowish hair markings as well. [5] The underside fur markings tend to be lighter beige to whitish. [5] The tail may be gray to black and often lighter below. [5]
Creeping voles have a relatively short tail, measuring less than 30% their total body length. [5] They have short ears, which are nearly hairless, though a few black hairs present. [5] They protrude just slightly from the fur around the head. [5] They have eight mammae, with two pairs present in each of the pectoral and inguinal regions. [5]
The skull of the creeping vole has a low, flat profile, with a long and slender snout. [5] The zygomatic arches are somewhat delicate. [5] The incisive foramen is short and wide, but not so much as to be a distinguishing feature. [5] They have small molars. [5]
Creeping voles are found in British Columbia in Canada and in Washington, Oregon and northern California, in the United States. [1] They are found as far north as Port Moody, British Columbia and as far south as Mendocino City, California. [5] The western range in Washington extends east to Mount Aix, Lake Chelan, and Signal Peak. [5] The range in Oregon extends east to the north base of Three Sisters and to Crater Lake. [5] There are variable reports as to their occurrence in the Willamette Valley of Oregon. [5] In California, they are found as far east as Beswick and South Yolla Bolly Mountain. [5]
They are found in coniferous forests and woodlands, grasslands, and chaparral. [2] They are found at sea level through altitudes of nearly 2,400 m (7,900 ft). [5] They are more populous in areas of disturbance than virgin forests. [2] They are burrowing animals and will also use fallen logs, other debris, and patches of grass for cover. [2] The burrows are shallow. [2] They are found in moist forests along the coast, but may do well in drier areas. [2]
It is suspected that ancestral voles migrated from Eurasia 1.2 million years ago. [5] However, no Pleistocene-era fossils of creeping voles have been identified. [5]
Creeping voles establish nests of dry grass in protected areas, such as under logs. [1] The breeding season varies by latitude, but is mainly March to September in Oregon and British Columbia. [1] Gestation lasts around 23 days. Each litter bears three to four young and the females may produce four or five litters a year. [1] The naked, pink newborn young weigh around 1.6 g (1⁄16 oz). [11] Their eyes are closed and skin flaps cover the ear openings. [11]
Creeping voles are primarily nocturnal, though they are sometimes active during the day. [1] They are herbivorous, probably eating forbs and grasses, as well as fungi. [1]
Creeping vole females have XO sex chromosomes, while males have XY. Evolutionary geneticists have investigated these sex chromosomal features of creeping voles. A models for the evolution of creeping vole sex chromosomes was published by researchers from the University of Edinburgh in 2001. [12] Recently, it was discovered the Y chromosome has been lost, the male-determining chromosome is a second X that is largely homologous to the female X, and both the maternally inherited and male-specific sex chromosomes carry vestiges of the ancestral Y. This is quite unusual in mammals, as the XY system is fairly stable across a number of mammal species. [13]
Although it is not widely distributed and not always common, the creeping vole is listed as "Least Concern" by the IUCN Red List. [1] The justifications for the listing are the lack of major threats, the stability of populations, and the adaptability of the animal to environmental changes. [1] Treatment of Douglas-fir plantations with herbicides in British Columbia did not affect creeping vole populations. [1] No conservation concerns are raised, since there are thought to be sufficient areas of protected habitat within its range. [1] NatureServe lists the species as secure within its range. [2]
Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molars. They are sometimes known as meadow mice or field mice in North America.
The European water vole or northern water vole, is a semi-aquatic rodent. It is often informally called the water rat, though it only superficially resembles a true rat. Water voles have rounder noses than rats, deep brown fur, chubby faces and short fuzzy ears; unlike rats their tails, paws and ears are covered with hair.
The Arvicolinae are a subfamily of rodents that includes the voles, lemmings, and muskrats. They are most closely related to the other subfamilies in the Cricetidae. Some authorities place the subfamily Arvicolinae in the family Muridae along with all other members of the superfamily Muroidea. Some refer to the subfamily as the Microtinae or rank the taxon as a full family, the Arvicolidae.
The Townsend's mole is a fossorial mammal in the family Talpidae, and is the largest North American mole. It was named after the American naturalist John Kirk Townsend. The name was selected at the request of Thomas Nuttall as a patronym to honor Townsend's contribution.
Microtus is a genus of voles found in North America, Europe and northern Asia. The genus name refers to the small ears of these animals. They are stout rodents with short ears, legs and tails. They eat green vegetation such as grasses and sedges in summer, and grains, seeds, root and bark at other times. The genus is also called "meadow voles".
The North American water vole or just water vole is the largest North American vole. It is found in the northwestern United States and southern parts of western Canada. This animal has been historically considered a member of genus Arvicola, but molecular evidence demonstrates that it is more closely related to North American Microtus species. Water voles are on the USDA Forest Service Region 2 sensitive species list because they maintain very small populations and there is high concern that their required habitat may be declining.
The singing vole, is a medium-sized vole found in northwestern North America, including Alaska and northwestern Canada.
The long-tailed vole, in some areas known as the San Bernardino long-tailed vole, is a small vole found in western North America. They have short ears and a long tail. Their fur is gray brown with light gray underparts. They are around 18 cm (7.1 in) long with an 8 cm (3.1 in) tail and weigh about 50 g (1.8 oz).
The gray-tailed vole also known as the gray-tailed meadow vole or gray-tailed meadow mouse, is a rodent in the genus Microtus of the family Cricetidae. Voles are small mammals, and this species lies roughly in the middle of their size range. First collected in 1895, it is endemic to the Willamette Valley, Oregon, and Clark County, Washington, in the Pacific Northwest region of North America. Historically, they were found in the prairie areas of the Valley and, though many of these areas have been converted for agricultural purposes, these animals remain common. For reasons that remain unclear, vole population densities in any area may fluctuate widely from season to season and year to year. They are preyed upon by owls, hawks, and carnivorous mammals, and their parasites include fleas and ticks. These voles build burrows and complex tunnel networks, which they sometimes share with other burrowing animals. Relatively little is known about their behavior in the wild, because they are elusive and unlikely to enter traps.
The western spotted skunk is a spotted skunk of western North America.
The California vole is a type of vole which lives throughout much of California and part of southwestern Oregon. It is also known as the "California meadow mouse", a misnomer as this species is a vole, not a mouse. It averages 172 mm (6.8 in) in length although this length varies greatly between subspecies.
Cabrera's vole is a species of vole native to Spain and Portugal. It is named for Ángel Cabrera, a mammalogist then working at the Museo Nacional de Ciencias Naturales in Madrid. It is the only living member of the subgenus Iberomys, although two fossil species are also known, including M. brecciensis, the likely direct ancestor of the living species.
Townsend's vole is a species of rodent in the family Cricetidae, the sister species of M. canicaudus. It is found in temperate grasslands of British Columbia in Canada and in the states of Washington and Oregon in the United States.
The Zempoaltépec vole is a species of rodent in the family Cricetidae. The name Microtus is from the Greek word mikros meaning small and otus meaning ear. The name umbrosus could be from the Latin umbros meaning shady. It is rather large and has a long tail when compared with other voles. Its pelage is long and soft. In the upper parts, the hair is uniformly dusky with brown tips and the lower parts a dark grey thinly washed with a reddish yellow color. It is found only in Mexico, in a semi-isolated mountain range southeast of the Cajones River in Mixes district, in Oaxaca.
The Columbian ground squirrel is a species of rodent common in certain regions of Canada and the northwestern United States. It is the second largest member of the genus Urocitellus, which is part of the tribe Marmotini, along with marmots, chipmunks, prairie dogs, and other holarctic ground squirrels. They are stout, with short dense fur, which is characteristically tawny across the bridge of the nose. Social encounters sometimes are initiated with kissing behavior and the most common activity above ground is standing at attention. Residing in mountainous terrain and high plains in northern latitudes, they hibernate for 8 to 9 months of the year in burrows, which may be used for many years. They are emaciated when emerging in the spring. The Columbian ground squirrel came to the attention of the scientific community through writings produced by Lewis and Clark, while 21st century molecular genetics has more finely illuminated its ties with other close relatives.
The camas pocket gopher, also known as the camas rat or Willamette Valley gopher, is a rodent, the largest member in the genus Thomomys, of the family Geomyidae. First described in 1829, it is endemic to the Willamette Valley of northwestern Oregon in the United States. The herbivorous gopher forages for vegetable and plant matter, which it collects in large, fur-lined, external cheek pouches. Surplus food is hoarded in an extensive system of tunnels. The dull-brown-to-lead-gray coat changes color and texture over the year. The mammal's characteristically large, protuberant incisors are well adapted for use in tunnel construction, particularly in the hard clay soils of the Willamette Valley. The gophers make chattering sounds with their teeth; males and females make purring sounds when they are together, and the young make twittering sounds. Born toothless, blind and hairless, the young grow rapidly before being weaned at about six weeks of age.
Mynomes is a North American subgenus of voles in the genus Microtus. Species in this subgenus are:
Igor Zagorodniuk is a Ukrainian zoologist, mammalogist, ecologist, and founder of Theriological school. He is a laureate of the State Prize of Ukraine in the field of science and technology (2015), and the author of more than 500 scientific publications.
Microtini is a tribe of voles in the subfamily Arvicolinae.
Footnotes:
Sources: