Northern Red-backed Vole

The Northern Red-backed Vole is a small, hardy rodent native to boreal forests and tundra edges across the Holarctic region. It is easily recognized by its bright reddish-brown dorsal stripe contrasting with grayish flanks. This species plays a key ecological role as a primary prey item for numerous boreal predators and is remarkable for its ability to remain active year-round beneath snow cover.

Boreal and subarctic regions of North America and Eurasia, including Alaska, Canada, Siberia, and northern Scandinavia

Widely distributed across the Holarctic: from Scandinavia through Siberia and the Russian Far East, into Alaska and northern Canada (Yukon, Northwest Territories, northern British Columbia), extending into subarctic tundra margins.

Altitude and depth

Sea level up to approximately 1500-2000m in mountainous boreal regions, depending on latitude and local forest cover.

Seasonal movements

Remains active year-round, including winter, relying on subnivean (under-snow) tunnels and nests to survive extreme cold; does not hibernate but may reduce activity during the coldest periods.

Prefers coniferous and mixed boreal forests, especially areas with dense moss cover, fallen logs, and shrubby understory; also found in tundra shrub zones, forest edges, and occasionally in disturbed or regenerating forest stands.

Adaptations to its environment

Dense fur coat and small body size help minimize heat loss in extreme cold; strong digging ability allows construction of insulated nests under snow and leaf litter; efficient cecal digestion allows utilization of fibrous winter vegetation like bark, lichens, and seeds.

Listed as Least Concern by the IUCN due to its extremely wide range, large population size, and lack of significant range-wide threats or major population declines.

Estimated population

Population size is not precisely quantified but is considered abundant and stable across most of its range, with natural multi-year population cycles typical of many vole species.

No major threats at the species level; localized impacts may include habitat alteration from logging, climate change affecting boreal forest composition, and increased predation pressure during population cycles.

Diseases and parasites

Known to host various ectoparasites such as fleas and mites, as well as endoparasites including nematodes and cestodes; can also be a reservoir for certain hantaviruses.

No specific conservation programs are dedicated to this species due to its stable status; general boreal forest conservation and protected areas across its range indirectly support its populations.

Recommended actions

Continued monitoring of boreal forest health and climate impacts; maintaining forest connectivity and understory complexity to support natural population cycles.

Distinctive bright rusty-red to chestnut stripe runs down the back from head to tail base, contrasting with grayish or buffy-gray sides and a pale grayish-white underside; ears are small and rounded, eyes are dark and prominent.

Size

Body length typically 8-11 cm, with a tail length of about 3-5 cm.

Weight

Adults typically weigh between 15-35 grams, with slight seasonal variation in body mass.

Distinctive features

The vivid reddish dorsal stripe is more pronounced and brighter than in related species like the Southern Red-backed Vole (Myodes gapperi), and its range extends further north into Arctic tundra edges.

Differences between males and females

Minimal sexual dimorphism; males and females are similar in size and coloration, though males may be marginally larger during breeding season.

Generally solitary outside of breeding season, though home ranges may overlap; not strongly territorial, with some tolerance of nearby conspecifics especially in favorable habitat patches.

When it is active

Primarily nocturnal and crepuscular, but can be active throughout the day and night, especially under snow cover in winter where light cues are less relevant.

Diet

Omnivorous, feeding mainly on seeds, berries, fungi, mosses, lichens, bark, and green vegetation; will also consume small invertebrates opportunistically.

Communication

Communicates through scent marking via glandular secretions to signal reproductive status and territory use, along with ultrasonic vocalizations and body postures for social interactions.

Interactions with other species

Serves as a key prey species for weasels, foxes, owls, hawks, and other boreal predators; competes with other small rodents such as deer mice and shrews for food and nesting sites.

Role in its ecosystem

Functions as an important link in boreal food webs, transferring energy from plant material to a wide range of predators; also contributes to seed dispersal and fungal spore distribution through its diet.

Breeding season occurs from spring through late summer (May to September), with females capable of producing 2-3 litters per year; gestation lasts about 17-21 days, with litters averaging 4-8 pups.

Raising the young

Females provide sole parental care, nursing and protecting young in a nest until weaning at approximately 3 weeks of age; young reach independence shortly after weaning.

Maturity and lifespan

Reaches sexual maturity at around 2-3 months of age; typical lifespan in the wild is short, often less than 1 year, though some individuals may survive up to 18 months.

Classification

Class Mammalia > Order Rodentia > Family Cricetidae > Genus Clethrionomys (sometimes Myodes) > Species C. rutilus

Subspecies

Several subspecies recognized across its vast Holarctic range, including Clethrionomys rutilus dawsoni (Alaska/Yukon), C. r. albiventer, and various Siberian populations; taxonomy remains debated with some authorities using Myodes rutilus.

Scientific synonyms

Myodes rutilus (alternative genus placement widely used in recent literature); Evotomys rutilus (older synonym)

Recent studies

Recent genetic studies have focused on phylogeography across its Holarctic range, revealing distinct lineages between Eurasian and North American populations shaped by Pleistocene glacial cycles.

Genome and DNA

Diploid chromosome number is 2n=56, with karyotype studies used to help distinguish closely related Clethrionomys/Myodes species.

Compared with similar species

Similar to the Southern Red-backed Vole (Myodes gapperi) but distinguished by a more northern range, brighter red dorsal coloring, and slightly smaller body size; also resembles other Microtus voles but has a more distinct bicolor pattern.

Despite freezing boreal winters, this vole remains active under the snow in a hidden world of tunnels called the subnivean zone; its population can fluctuate dramatically in multi-year cycles influencing entire predator communities; it can climb into low shrubs and trees to forage on buds and bark.

Where and how to see it

Best observed in boreal forests of Alaska, Yukon, or Siberia during summer evenings near fallen logs, mossy ground, and forest edges; using small live traps or careful quiet observation increases chances of sighting.

Risks to humans

No notable risk to humans, though as with many rodents, there is a low potential for disease transmission such as hantavirus through contact with droppings or nesting material.