Definition
The gray-tailed vole (Microtus canicaudus) is a small North American rodent belonging to the family Cricetidae. It is characterized by a relatively long, gray‑colored tail and is one of several species within the genus Microtus.
Overview
Gray-tailed voles are native to the western United States, primarily occupying the intermountain region that includes parts of Oregon, Nevada, Utah, and Idaho. They inhabit open sagebrush steppe, grasslands, and semi‑arid shrub‑steppe ecosystems, often favoring areas with loose, well‑drained soils suitable for burrowing. The species is primarily nocturnal and exhibits seasonal fluctuations in population density, with peaks in spring and early summer following breeding cycles.
Etymology/Origin
The common name derives directly from the animal’s distinctive tail coloration—gray on the dorsal surface and typically lighter ventrally. The generic name Microtus comes from Greek roots “micro‑” (small) and “ous” (ear), referencing the small ears typical of voles. The specific epithet canicaudus combines Latin “cani‑” (gray) and “caudus” (tail), literally meaning “gray‑tailed”.
Characteristics
- Physical description: Adults measure 10–13 cm in total length, with the tail comprising about 30–40 % of that length (approximately 3–5 cm). Body mass ranges from 20 to 35 g. Fur is dense, brownish‑gray on the back and paler on the ventral side; the tail is uniformly gray. Ears are small and concealed by fur.
- Dental formula: 1.0.0.3 / 1.0.0.3 (total of 16 teeth), typical of cricetid rodents.
- Reproduction: Breeding occurs from early spring through late summer. Females can produce 2–4 litters per season, each comprising 3–7 offspring after a gestation period of about 21 days. Young are weaned at roughly three weeks of age.
- Diet: Primarily herbivorous, feeding on grasses, forbs, seeds, and occasionally small insects. Seasonal diet shifts reflect availability of vegetation.
- Behavior: Gray-tailed voles construct complex burrow systems with nesting chambers and food storage. They are solitary or live in loose family groups, communicating via scent marking and vocalizations.
- Predators and threats: Common predators include raptors, snakes, and small carnivorous mammals such as weasels and foxes. Habitat alteration due to agriculture and urban development can locally reduce populations, though the species remains relatively abundant.
- Conservation status: The International Union for Conservation of Nature (IUCN) classifies the gray-tailed vole as “Least Concern” due to its wide distribution and stable overall population trends.
Related Topics
- Microtus (genus) – overview of related vole species.
- Sagebrush steppe ecosystem – primary habitat type for the gray-tailed vole.
- Rodent population dynamics – studies on cyclic fluctuations in vole populations.
- Conservation biology of small mammals – frameworks for assessing species like the gray-tailed vole.