California Vole
Encyclopedia
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. It averages 172 millimetres (6.8 in) in length although this length varies greatly between subspecies.
The body is covered with cinnamon to tawny olive fur, ticked with occasional darker hairs, and fading to a medium grey on the underside. The tail is black above and grey below. The whiskers and feet are grey in color, and there is a patch of white fur near the anus
. There is some variation between subspecies, with those native to more highland habitats tending to be more reddish in color, and those in marshier environments tending to be darker. Males have a pair of scent gland
s on the hips, which are used to mark their trackways. Females have four pairs of teats, two in the chest, and two closer to the groin.
in Baja California
in the south, through much of California
and as far as Eugene
, Oregon
in the north. It is, however, absent from most of the deserts of south eastern California and from the extreme north eastern and north western corners of the state. It inhabits a range of different grassland
habitats, from wet coastal marsh
land to dry uplands and savannah
.
The California vole is herbivorous
, feeding mainly on grass
es and sedge
s, supplemented by other flowering herbs. Preferred foods include wild oat
s, ryegrass
, and brome grass
, although all of these are introductions from Europe, and therefore cannot represent the animal's original diet. California voles can become an agricultural pest, causing widespread damage especially to fields of artichoke
s, but also to crops such as alfalfa
, potato
es, and asparagus
.
Because the California vole is relatively common and widespread, it has numerous natural predators, including hawk
s, owl
s, egret
s, long-tailed weasel
s, coyote
s, cat
s, and rattlesnake
s.
or nocturnal. However, they spend much of their time below ground, using burrows connected by above ground runways that they use to find food. Home ranges are relatively small, with the animals rarely venturing far from their burrows; averages of 103 square metres (123.2 sq yd) for males and 68 square metres (81.3 sq yd) for females have been reported. The larger ranges of males overlap with the ranges of several nearby females, but they are generally aggressive towards other nearby males, clawing and biting any intruders. Although they also sometimes use abandoned gopher
tunnels, burrows dug by the voles themselves are blind-ending and range from 1.5 to 12 m (4.9 to 39.4 ft) in length. The voles construct nests of dried grass within their burrows; these have a single entrance, and are typically between 7 and 15 cm (2.8 and 5.9 in) below the surface.
The voles are active above ground primarily to find food, reaching the seeds on high grasses by standing on their hind legs and clipping the stems with their teeth. They often carry the food back to their burrow to eat it, although they do not hoard food or hibernate through the winter. California voles are often found in groups of a single male, one or more females, and a number of young, and the male may assist the female in construction of her nest before she gives birth. California voles are reasonably strong swimmers, and may use this tactic to attempt to escape from predators.
as some other voles. Copulation can be prolonged and repeated, and is followed by formation of a copulatory plug and by induced ovulation. Gestation
lasts three weeks and results in the birth of up to ten young, with four or five being most common. The female is ready to breed again with fifteen hours of giving birth, and may give birth to several litters over the course of their life.
The young are born hairless and blind, weighing an average of 2.8 gram (0.0987670938943135 oz). They begin to grow fur within five days of birth, and their eyes open at nine days, although they are capable of sensing light before this. The young are weaned
at around two weeks of age, and have a full set of adult teeth by three weeks. Females reach sexual maturity after as little as three weeks, while males become sexually mature after six weeks. The lifespan is correspondingly short, with individuals living for less than a year, even in the absence of predators.
genus are known from California as far back as 1.2 million years ago, although it is unclear whether these represent California voles specifically, or a related, possibly extinct, species. Genetic evidence suggests that the closest extant relative of the California vole is most likely the Mexican vole
, Microtus mexicanus, and the species is known to be able to produce infertile hybrids with other closely related species, such as the montane vole
. Indeed, matings between northern and southern subspecies of California vole do not always produce fertile offspring, with male hybrids in particular typically being infertile. This may indicate that some of the subspecies are in the process of diverging into separate species, and it has even been proposed that the California vole may already represent two different species.
Vole
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 . There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America...
which lives throughout much of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and part of southwestern Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. It is also known as the California meadow mouse. It averages 172 millimetres (6.8 in) in length although this length varies greatly between subspecies.
Description
The California vole is a medium sized vole, and a fairly typical member of its group in appearance. Males range from 152 to 196 mm (6 to 7.7 in) in head-body length, with a 42 to 58 mm (1.7 to 2.3 in) tail. Females are significantly smaller at 149 to 182 mm (5.9 to 7.2 in) in length with a 38 to 53 mm (1.5 to 2.1 in) tail. Males weigh from 41 to 81 g (1.4 to 2.9 oz), and females from 36 to 63 g (1.3 to 2.2 oz). There is, however, considerable variation between different subspecies, with the southern subspecies tending to be larger than those found further north.The body is covered with cinnamon to tawny olive fur, ticked with occasional darker hairs, and fading to a medium grey on the underside. The tail is black above and grey below. The whiskers and feet are grey in color, and there is a patch of white fur near the anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
. There is some variation between subspecies, with those native to more highland habitats tending to be more reddish in color, and those in marshier environments tending to be darker. Males have a pair of scent gland
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...
s on the hips, which are used to mark their trackways. Females have four pairs of teats, two in the chest, and two closer to the groin.
Distribution and habitat
The California vole is found from El RosarioEl Rosario, Baja California
El Rosario is a small town on the west coast of the state of Baja California on Highway 1, 61 kmsouth of San Quintín and 119 km north of Cataviña. The census of 2010 reported a population of 1,704 inhabitants...
in Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
in the south, through much of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and as far as Eugene
Eugene, Oregon
Eugene is the second largest city in the U.S. state of Oregon and the seat of Lane County. It is located at the south end of the Willamette Valley, at the confluence of the McKenzie and Willamette rivers, about east of the Oregon Coast.As of the 2010 U.S...
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
in the north. It is, however, absent from most of the deserts of south eastern California and from the extreme north eastern and north western corners of the state. It inhabits a range of different grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
habitats, from wet coastal marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
land to dry uplands and savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
.
Subspecies
Seventeen subspecies are currently recognized, some of which are protected. They include:- M. c. californicus - San Francisco region
- M. c. equivocatus - Baja California
- M. c. aestuarinus - central California
- M. c. constrictus - Humboldt County, CaliforniaHumboldt County, CaliforniaHumboldt County is a county in the U.S. state of California, located on the far North Coast 200 miles north of San Francisco. According to 2010 Census Data, the county’s population was 134,623...
- M. c. eximus - Oregon and north-central California
- M. c. grinelli - Sierra JuarezSierra JuárezSierra de Juárez is a mountain range on the Baja California Peninsula, of Baja California, Mexico. It is part of the Peninsular Ranges. The Laguna Mountains of California lie to the north and the Sierra San Pedro Mártir lies to the south....
, Baja California - Monterey Vole, M. c. halophilus - Monterey BayMonterey BayMonterey Bay is a bay of the Pacific Ocean, along the central coast of California. The bay is south of San Francisco and San Jose, between the cities of Santa Cruz and Monterey....
, California - M. c. huperuthrus - Baja California
- M. c. kernensis - Kern County, California
- M. c. mariposae - central eastern California
- Mojave River Vole, M. c. mohavensis (CDFG special concern) - Mojave DesertMojave DesertThe Mojave Desert occupies a significant portion of southeastern California and smaller parts of central California, southern Nevada, southwestern Utah and northwestern Arizona, in the United States...
- M. c. paludicola - Alameda County, California
- M. c. sanctidiegi - south western California
- San Pablo Vole, M. c. sanpabloensis (CDFG special concern) - Contra Costa County, California
- Amargosa Vole, M. c. scirpensis (Federal and State endangered) - Panamint RangePanamint RangeThe Panamint Range is a short rugged fault-block mountain range on the northern edge of the Mojave Desert, in Death Valley National Park, Inyo County, California, United States.-Geography:...
, California - South Coast Marsh Vole, M. c. stephensi (CDFG special concern) - Los AngelesLos ÁngelesLos Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
region - Owens Valley Vole, M. c. vallicola (CDFG special concern) - White MountainsWhite Mountains (California)The White Mountains of California are a triangular fault block mountain range facing the Sierra Nevada across the upper Owens Valley. They extend for approximately as a greatly elevated plateau about wide on the south, narrowing to a point at the north, with elevations generally increasing...
, California
Ecology
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, feeding mainly on grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
es and sedge
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...
s, supplemented by other flowering herbs. Preferred foods include wild oat
Avena fatua
Avena fatua is a species of grass in the oat genus. It is known as the common wild oat. This oat is native to Eurasia but it has been introduced to most of the other temperate regions of the world. It is naturalized in some areas and considered a noxious weed in others...
s, ryegrass
Lolium multiflorum
Lolium multiflorum is a ryegrass native to temperate Europe, although the precise location of its origin is unknown....
, and brome grass
Bromus
Bromus is a large genus of the grass family . Estimates in the scientific literature of the number of species have ranged from 100 to 400, but plant taxonomists currently recognize around 160–170 species...
, although all of these are introductions from Europe, and therefore cannot represent the animal's original diet. California voles can become an agricultural pest, causing widespread damage especially to fields of artichoke
Artichoke
-Plants:* Globe artichoke, a partially edible perennial thistle originating in southern Europe around the Mediterranean* Jerusalem artichoke, a species of sunflower with an edible tuber...
s, but also to crops such as alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
, potato
Potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
es, and asparagus
Asparagus
Asparagus officinalis is a spring vegetable, a flowering perennialplant species in the genus Asparagus. It was once classified in the lily family, like its Allium cousins, onions and garlic, but the Liliaceae have been split and the onion-like plants are now in the family Amaryllidaceae and...
.
Because the California vole is relatively common and widespread, it has numerous natural predators, including hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s, owl
Owl
Owls are a group of birds that belong to the order Strigiformes, constituting 200 bird of prey species. Most are solitary and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish...
s, egret
Egret
An egret is any of several herons, most of which are white or buff, and several of which develop fine plumes during the breeding season. Many egrets are members of the genera Egretta or Ardea which contain other species named as herons rather than egrets...
s, long-tailed weasel
Long-tailed Weasel
The long-tailed weasel , also known as the bridled weasel or big stoat is a species of mustelid distributed from southern Canada throughout all the United States and Mexico, southward through all of Central America and into northern South America.-Evolution:The long-tailed weasel is the product of...
s, coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s, and rattlesnake
Rattlesnake
Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae . There are 32 known species of rattlesnake, with between 65-70 subspecies, all native to the Americas, ranging from southern Alberta and southern British Columbia in Canada to Central...
s.
Behavior
California voles are crepuscularCrepuscular
Crepuscular animals are those that are active primarily during twilight, that is during dawn and dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is, thus, in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright...
or nocturnal. However, they spend much of their time below ground, using burrows connected by above ground runways that they use to find food. Home ranges are relatively small, with the animals rarely venturing far from their burrows; averages of 103 square metres (123.2 sq yd) for males and 68 square metres (81.3 sq yd) for females have been reported. The larger ranges of males overlap with the ranges of several nearby females, but they are generally aggressive towards other nearby males, clawing and biting any intruders. Although they also sometimes use abandoned gopher
Gopher
- Animal kingdom :* Gopher , including:** Pocket gophers , about 40 species distributed from North America to Colombia** Several ground squirrels of North America, particularly those formerly classified as Spermophilus* Gopher tortoise , distributed in North America- Other uses :* Minnesota, the...
tunnels, burrows dug by the voles themselves are blind-ending and range from 1.5 to 12 m (4.9 to 39.4 ft) in length. The voles construct nests of dried grass within their burrows; these have a single entrance, and are typically between 7 and 15 cm (2.8 and 5.9 in) below the surface.
The voles are active above ground primarily to find food, reaching the seeds on high grasses by standing on their hind legs and clipping the stems with their teeth. They often carry the food back to their burrow to eat it, although they do not hoard food or hibernate through the winter. California voles are often found in groups of a single male, one or more females, and a number of young, and the male may assist the female in construction of her nest before she gives birth. California voles are reasonably strong swimmers, and may use this tactic to attempt to escape from predators.
Reproduction
California voles are able to breed almost year round, although most breeding occurs during the middle of the wet season, from March to April. Males may breed with more than one female, although the species is not as strongly polygynousPolygyny
Polygyny is a form of marriage in which a man has two or more wives at the same time. In countries where the practice is illegal, the man is referred to as a bigamist or a polygamist...
as some other voles. Copulation can be prolonged and repeated, and is followed by formation of a copulatory plug and by induced ovulation. Gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
lasts three weeks and results in the birth of up to ten young, with four or five being most common. The female is ready to breed again with fifteen hours of giving birth, and may give birth to several litters over the course of their life.
The young are born hairless and blind, weighing an average of 2.8 gram (0.0987670938943135 oz). They begin to grow fur within five days of birth, and their eyes open at nine days, although they are capable of sensing light before this. The young are weaned
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...
at around two weeks of age, and have a full set of adult teeth by three weeks. Females reach sexual maturity after as little as three weeks, while males become sexually mature after six weeks. The lifespan is correspondingly short, with individuals living for less than a year, even in the absence of predators.
Evolution
Fossils of members of the MicrotusMicrotus
The genus Microtus is a group of voles found in North America, Europe and northern Asia. The genus name refers to the small ears of these animals. There are 62 species in the genus....
genus are known from California as far back as 1.2 million years ago, although it is unclear whether these represent California voles specifically, or a related, possibly extinct, species. Genetic evidence suggests that the closest extant relative of the California vole is most likely the Mexican vole
Mexican Vole
The Mexican Vole is a species of rodent in the family Cricetidae. It is found in Mexico and the United States.-References:...
, Microtus mexicanus, and the species is known to be able to produce infertile hybrids with other closely related species, such as the montane vole
Montane Vole
The Montane Vole is a species of rodent in the family Cricetidae.It is found in the western United States and British Columbia in Canada.-References:...
. Indeed, matings between northern and southern subspecies of California vole do not always produce fertile offspring, with male hybrids in particular typically being infertile. This may indicate that some of the subspecies are in the process of diverging into separate species, and it has even been proposed that the California vole may already represent two different species.