Microtus that is found on all northern continents. In the Nearctic, it is found from the extreme northern edge of British Columbia northward to the Arctic coast, and from western Northwest Territories, through Yukon Territory and nearly all of Alaska. It has the northernmost distribution of any Microtus species in North America, with occurrences to around 71°N in Alaska. In the Palearctic, tundra voles occupy a somewhat broader range, extending from Scandinavia and the Netherlands in the west, throughout northern Europe and Asia to Siberia in the east, and south as far as Mongolia. (Hoffmann and Koeppl, 1985; Musser and Carleton, 2005)(pronounced e-KON-uh-mus), commonly known as the tundra or root vole, is one of only four Holarctic rodents and the only species of
Tundra voles display sexual size dimorphism, with adult males roughly 30% larger than females. The size and weight of the species is also variable relative to latitude and geography, especially so in the Palearctic. Individuals in populations at higher latitudes are generally larger and have proportionally smaller tails as a possible adaptation to colder temperatures. In addition, insular subspecies are generally larger than continental counterparts. Weight ranges from 25 to 80 g, with an average around 50 g. Total length ranges from 118 mm in the Old World, to 226 mm in the larger subspecies found in the New World. The tail is relatively short, generally being less than 30% of the total length. The name Microtus means “small ear” and refers to the short ears hidden in pelage that are a characteristic common to members of the genus. The dental formula for follows the basic pattern for all Microtus: incisors 1/1, canines 0/0, premolars 0/0, molars 3/3. (Bondrup-Nielsen and Ims, 1990; Gromov and Polyakov, 1992; Hall, 1981; Lance and Cook, 1998; MacDonald, 2003; Nagorsen, 2002; Ringens, et al., 1977; Wilson and Ruff, 1999)
Female tundra voles are polyestrous and often produce two to three litters per year. The breeding season generally lasts from late April to September during years with peak densities, and is around one to two months shorter in years of low densities. Winter breeding has been observed very rarely, and is attributed to unusually warm summers resulting in late fall re-growth. (Kaikusalo and Tast, 1984; Nowak, 1999; Whitney, 1976; Wilson and Ruff, 1999)
Females provide the greater investment in the offspring, including nest construction, protection, and care of the young. However, increases in paternal investment in southern populations of tundra voles have been observed. It has been suggested that this is a result of longer foraging times required by southern females during lactation due to increased resource limitation at lower latitudes. (Ims, 1997)
Males generally occupy and utilize much larger territories than females, and this territory size is positively correlated with body size. Territories can range up to 3900 m^2 for males, but average 804 m^2 and have little overlap occurring between them. Females occupy much smaller territories, averaging 377 m^2, but are more philopatric than males and may share a territory with several other related females. The majority of male territories contain several female territories, and the resident male will often defend the breeding rights to all of the females contained within. Males travel approximately twice as far as females and may utilize an area as large as 12,000 m^2 in a single day. (Gliwicz, 1997; Lambin, et al., 1992; Litvin and Karaseva, 1968; Tast, 1966)
Tundra voles are strictly vegetarian and preferentially feed on sedges (Carex sp. and Eupharium sp.) that grow in their favored habitat of wet, marshy tundra. Sedges make up around 70 to 80% of their diet, with the remainder comprising herbs, mosses, lichen, and small woody shrubs. These percentages vary seasonally, and a 30% decrease in sedge consumption is common in winter, with mosses and lichens becoming a relatively major component of the diet. Other plant foods that are preferred when available include Equisetum sp., Dryas integrifolia, Salix sp. and various grasses. (Batzli and Lesieutre, 1991; Tast, 1966)
In the fall, (Wilson and Ruff, 1999)creates large caches of stored seeds and rhizomes to supplement its winter diet. Native peoples of North America occasionally sought out these caches in order to obtain large quantities of desired foods, such as licorice root.
Vulpes lagopus) in Alaska. Other known terrestrial predators of include weasels, martens, red foxes, and wolverines. In addition, numerous avian species prey on tundra voles, including owls, falcons, hawks, jaegers, gulls, and shrikes. (Anthony, et al., 2000; Sundell, et al., 2004; Wilson and Ruff, 1999)is an important prey source for many carnivores. During cycles of peak density, they have been known to comprise the majority of the diet for species such as the arctic fox (
Populations of M. longicaudus, M. pennsylvanicus, M. agrestis and M. xanthognathus) but generally either avoid competition through niche specialization, or out-compete the other species, as in the case of M. agrestis. (Tast, 1968; Whitney, 1976)experience cyclical fluctuations, reaching peak densities of 70 to 80 voles per hectare. As explained above, during these peak density years, tundra voles provide a large food base for many predator species. When present in such large numbers, they can also significantly alter the biological production of the tundra ecosystem through their foraging activities. Tundra voles share their habitat preferences with several similar species (e.g.,
Tundra voles are host to a variety of internal and external parasites. Endoparasites include cestodes (Echinococcus sp., Paranoplocephala sp., and Taenia sp.), nematodes (Heligmosomoides sp.), and trematodes (Quinqueserialis nassalli). Ectoparasites include fleas (Siphonaptera sp.), lice (Polyplax sp.), and ticks (Ixodes angustus). (Timm, 1985)
Tundra voles are known carriers of several diseases. Of most importance to humans is the role of Francisella tularensis) that causes tularemia in humans. This disease is transmitted by direct contact and is fatal in about 7% of untreated human cases. Additionally, at peak densities they can compete with livestock for forage and cause damage to trees by gnawing on the roots. (Feldhamer, et al., 2003)as a carrier of the bacterium (
Overall, M. o. amakensis, M. o. elymocetes, M. o. innuitus, M. o. popofensis, M. o. punukensis, and M. o. sitkensis. Furthermore, two subspecies, M. o. mehelyi and M. o. arenicola, are categorized by the IUCN as “vulnerable” and “critically endangered”, respectively. Population declines in some subspecies have been attributed to habitat deterioration. In the case of M. o. arenicola, competition with M. arvalis has additionally contributed to population declines on some islands. (Gippoliti, 2006; Gippoliti, 2006)is a relatively stable species and not currently listed as threatened or endangered on any listing. It is also categorized by the IUCN as a species of “least concern”. However, insufficient knowledge of several isolated subspecies has resulted in their categorization of “data deficient” by the IUCN. These subspecies include
Tanya Dewey (editor), Animal Diversity Web.
Chad Bieberich (author), University of Alaska Fairbanks, Link E. Olson (editor, instructor), University of Alaska Fairbanks.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.
uses smells or other chemicals to communicate
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.
Found in northern North America and northern Europe or Asia.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
Having one mate at a time.
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
having more than one female as a mate at one time
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
places a food item in a special place to be eaten later. Also called "hoarding"
uses touch to communicate
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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