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 long with an tail and weigh about .
Taxonomy
The scientific name of the long-tailed vole is Microtus longicaudus. The generic name, Microtus, derives from the Greek words μικρός meaning "small" + οὖς "ear". In Latin, the species name longicaudus derives from longus meaning "long" and cauda meaning "tail". The type specimen was a female collected by Vernon Orlando Bailey in the Black Hills at an altitude around near Custer, South Dakota, on July 19, 1887. The description was published by C. Hart Merriam in The American Naturalist the following year. The original scientific name was Arvicola longicaudus. Certain features of the molars were noted, which distinguished the long-tailed vole from other voles known at the time. The species was formerly sometimes regarded as a member of the Old World genus Chionomys.
The Coronation Island vole, once considered to be a separate species, is now believed to be a subspecies.
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. An albino vole was also found in New Mexico.
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 testosterone. Each eyelid of the long-tailed vole has around 3-4 meibomian glands.
Fossil record
Fossil remains date towards the end of the Wisconsinian glaciation. Fossils have been collected from: Moonshiner Cave in Idaho; Agate Basin and Little Box Elder Cave in Wyoming; Chimney Rock Animal Trap in Colorado; and Burnet Cave and Dry Cave in New Mexico.
The fossil remains of long-tailed voles may be difficult to distinguish from those of similar small voles, such as the meadow vole and the montane vole. As such, collected fossils are identified based on probabilities of occurrence within the geographic range or with other associated species.
Distribution and habitat
thumb|Long-tailed voles may reside near marshes growing hardstem bullrush ([[Schoenoplectus acutus)]]
These animals are found in a wide variety of habitats, including alpine meadows and shrubby areas, often near streams.