Long-tailed vole
| Long-tailed vole | |
|---|---|
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Cricetidae |
| Subfamily: | Arvicolinae |
| Genus: | Microtus |
| Subgenus: | Pitymys |
| Species: | M. longicaudus
|
| Binomial name | |
| Microtus longicaudus (Merriam, 1888)
| |
| Subspecies | |
|
List[2]
| |
| |
| Distribution of the long-tailed vole | |
| Synonyms[3] | |
|
List
| |
The long-tailed vole (Microtus longicaudus), 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).
Taxonomy
The
The Coronation Island vole, once considered to be a separate species, is now believed to be a subspecies.[7]
Description
The long-tailed vole is a small terrestrial mammal.[3] They are around 18 cm (7.1 in) long with an 8 cm (3.1 in) tail. They weigh on average 50 g (1.8 oz).[8] They have a thick body and a relatively long tail.[3] The tail is bicolored and extends greater than one-third the animal's total length.[3] The type specimen measured 185 mm (7.3 in), with a 65 millimetres (2.6 in) tail and a 21 millimetres (0.83 in) hind foot.[5] The ear measured 14 millimetres (0.55 in) x 8 millimetres (0.31 in) x 13 millimetres (0.51 in).[5]
The long-tailed vole is similar in size to the
The middle upper molar lacks a posterior-internal loop or spur.[5] Merriam also noted some "peculiarities", not otherwise specified, in the original description, which distinguish the long-tailed vole from other species known in the late 1800s.[9] This first specimen Merriam described had large ears, with folds capable of closing the ear canal opening.[5] Relative to the overall length of the animal, the tail was longer than any other vole described at that time.[5] The fur is a sooty yellow-brown with some grizzled aspects.[5] There are hints of rust coloring on the mid back.[5] The whitish underside fur is a leaden gray towards the base.[5] The underside fur blends seamlessly with the fur on the sides of the vole.[5] The undersides of the tail are darker.[5] The feet are plumbeous, a leaden gray.[6]
The genitalia of the long-tailed vole have been described. The baculum has broad and straight proximal bone. It is similar in structure to that of the meadow vole, but with different proportions. The basal shaft is dumb-bell shaped in cross section and tapers to a blunt point at the end. The shaft is broad in dimension and connects via cartilaginous linkages to three lateral segments. The glans penis has a dorsal lobe elevated above a ventral rim. The rim has spiny fingerlike processes, but not the dorsal lobe.[10] A rod shaped os clitoridis may be present, in front of the urethra.[11]
Long-tailed voles can be found with unusual dentition. A female with grooved incisors was found in the Yukon. Several other voles from Oregon were found with flattened incisors and malocclusion of their incisors and molars. A specimen in New Mexico was reported with an extra tooth in the right lower jaw.[10] An albino vole was also found in New Mexico.[4]
Long-tailed voles do not usually have the hip glands, which are found in other members of the genus Microtus. These can develop if the animal is injected with
Fossil record
Fossil remains date towards the end of the
Distribution and habitat
These animals are found in a wide variety of habitats, including
In the Malheur National Wildlife Refuge, they reside among marshes of hardstem bullrush (Schoenoplectus acutus), cattail (Typha latifolia), baltic rush (Juncus balticus), and sedges (Carex sp.).[12]
They are found at elevations from sea level up to 3,650 m (11,980 ft) above sea level.[7] Near the southern and eastern limits of the geographic range, they tend to reside at higher elevations.[7] Their range extends throughout western North American. The northern limits are in east-central Alaska.[7] The range extends south through the western Canadian provinces of Alberta, British Columbia, Northwest Territories, and Yukon.[7] It extends south and east to include the states of: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, South Dakota, Utah, Washington, Wyoming.[7]
Behavior and ecology
Long-tailed voles are active year-round, usually during the day.[7] However, in Alaska, they have been observed nocturnally.[7] The usually are free ranging and do not make well defined runways.[7] The breeding season begins in May and extends through September or October, depending on location.[7] The female vole has on average two litters per year, but may have as few as 1 or as many as 4.[7] In northern areas, they may have only two litters over the course of their lifetime.[7] The size of the litter is typically four or five.[7] They may have as many as eight.[10] Long-tailed vole parents will respond to ultrasonic cries made by the newborns in distress.[4] It is unusual for long-tailed voles to live more than one year.[12] Females live longer than males.[12]
The long-tailed vole are apprehensive of other voles.
They feed on green plants, assorted berries, seeds, and fungi. During the winter, diet may consist of the inner bark of shrubs and trees.[7] During winters in Nevada, they have been observed eating bark and leaves of sagebrush.[12]
Predators include
Long-tailed vole populations can fluctuate widely over a period of time within a given locale. Populations densities are generally sparse, with around 5-16 voles per hectare, but this can increase to more than 40.[7]
Human interactions
Conservation status
The
References
Footnotes:
- .
- ^ a b Musser & Carleton 2005, p. 1004.
- ^ a b c d Smolen & Keller 1987, p. 1.
- ^ a b c d e f Smolen & Keller 1987, p. 5.
- ^ a b c d e f g h i j k l m n Merriam 1888, p. 934.
- ^ a b c d Bailey 1900, p. 48.
- ^ a b c d e f g h i j k l m n o p q r s IUCN Red List 2008.
- ^ Smolen & Keller 1987, p. 2.
- ^ Merriam 1888, p. 935.
- ^ a b c d e f g h i Smolen & Keller 1987, p. 3.
- ^ Ziegler, Alan C. "Occurrence of os clitoridis in Microtus." Journal of Mammalogy 42.1 (1961): 101-103.
- ^ a b c d e f g h i j Smolen & Keller 1987, p. 4.
- ^ Smolen & Keller 1987, pp. 4–5.
Sources:
- Bailey, Vernon (1900). Revision of American Voles of the Genus Microtus. U.S. Government Printing Office.
- Linzey, A.V. & Hammerson, G. (NatureServe) (2008). "Microtus longicaudus". IUCN Red List of Threatened Species. 2008. Retrieved 9 December 2014.
- Merriam, C Hart (October 1888). "Description of a new species of meadow mouse from the Black Hills of Dakota". The American Naturalist. 22 (262): 934–935. JSTOR 2451396.
- OCLC 62265494.
- Smolen, Michael J.; Keller, Barry L. (27 February 1987). "Microtus longicaudus" (PDF). Mammalian Species (271): 1–7. JSTOR 3503956. Retrieved 9 December 2014.