Townsend's vole (''Microtus townsendii'') is a species of
rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...
in the family
Cricetidae
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At over 870 species, it is either the largest or second-largest family ...
, the
sister species
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
of ''
M. canicaudus''. It is found in temperate
grassland
A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...
s of
British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
in
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
and in the states of
Washington and
Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
in the United States.
Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
root words for "small ear" are the source for the genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
name ''Microtus''. American naturalist and writer John Kirk Townsend
John Kirk Townsend (August 10, 1809 – February 6, 1851) was an American natural history, naturalist, ornithologist and collector.
Townsend was a Quaker born in Philadelphia, the son of Charles Townsend and Priscilla Kirk. He attended Westtow ...
collected the type specimen
In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...
in 1835, which accounts for the second part of the name.
Description
Townsend's vole is one of the largest voles in North America, growing to a total length of including a tail of , and a weight of . The ears are wide and prominent, being clearly visible above the fur, which is thin and coarse. The upper surface is dark brown with many guard hairs with black tips and the underparts are paler. The feet are slate grey and the tail is blackish above and dark brown beneath. Juveniles are generally darker than adults with dark grey underparts and black tails and feet.
Distribution and habitat
Townsend's vole is found in the extreme west of North America. Its range extends from Vancouver Island
Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...
, British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
southwards through Washington state and Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
to Humboldt Bay
Humboldt Bay (Wiyot language, Wiyot: ''Wigi'') is a natural bay and a multi-basin, bar-built coastal lagoon located on the rugged North Coast (California), North Coast of California, entirely within Humboldt County, California, Humboldt County, ...
in California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. It occurs from sea level to altitudes of in the Olympic Mountains
The Olympic Mountains are a mountain range on the Olympic Peninsula of the Pacific Northwest of the United States. The mountains, part of the Pacific Coast Ranges, are not especially high – Mount Olympus (Washington), Mount Olympus is the high ...
and in the Cascade Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...
.[ These voles typically live in wet meadows, marshes, flood plains, wet areas with rank vegetation and ]salt marshes
A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open Seawater, saltwater or brackish water that is regularly flooded by the ti ...
.
The population can become extremely dense, so that it impacts or excludes other species. Their proliferation rate makes them a good source of food for many species.
Biology
Townsend's vole lives in a burrow system and creates runways among the vegetation in its habitat. The runways are used all year round by successive generations of voles and may be deep. In the summer the voles may take advantage of the denser cover available and also move about elsewhere. Feces
Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...
are deposited in the runways and large latrines may form, often at intersections. These latrines have been reported as reaching dimensions of with a height of up to . Nests may be built on the surface of the ground or on hummocks, and this allows the vole to live in seasonally-flooded areas where its burrows are sometimes underwater. Both underground and surface nests are made of grasses.
Townsend's vole feeds on soft green plant material such as rushes, tules, grass
Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...
es, sedge
The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...
s, horsetail
''Equisetum'' (; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.
''Equisetum'' is a "living fossil", the only living genus of the entire subclass Equisetidae, which ...
s, clover
Clovers, also called trefoils, are plants of the genus ''Trifolium'' (), consisting of about 300 species of flowering plants in the legume family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with the highest diversit ...
s, alfalfa
Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial plant, perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, ...
, blue-eyed grass and purple-eyed grass. They also store the bulbous roots of American wild mint, consuming them during the winter even though plenty of succulent green food is available at that time.
Breeding takes place between February and October. The gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
period is about 23 days and the litter size ranges from one to nine young with an average of four, larger females usually having larger litters. The offspring are weaned at about sixteen days of age.
Status
Townsend's vole has a wide range and undergoes large swings in population. Over the long term, the population seems to be steady and in some localities this vole is very plentiful, having been recorded at densities as high as eight hundred individuals per hectare. No particular threats to this species have been recognised; the International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
assessed its conservation status as being of "least concern
A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
".[
]
References
Citations
Sources
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Further reading
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External links
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{{Taxonbar, from=Q1761552
Microtus
Mammals described in 1839
Taxonomy articles created by Polbot
Taxa named by John Bachman
Rodents of the United States
Rodents of Canada