Myodes californicus

California Red-backed Vole

Family: Cricetidae · Class: Mammalia · Order: Rodentia

The California red-backed vole is a small rodent endemic to the Pacific Coast region of California. Adults measure 85 to 115 mm (3.3 to 4.5 inches) in total length, with a tail length of 30 to 45 mm (1.2 to 1.8 inches). The body weight ranges from 15 to 25 grams (0.5 to 0.9 ounces). The species exhibits distinctive coloration with a reddish-brown dorsal stripe extending from the head to the base of the tail, contrasting with grayish-brown sides and a whitish-gray ventral surface. The ears are small and nearly hidden in the dense fur, and the tail is bicolored with dark upper surface and lighter underside. Historically, California red-backed voles occurred along the Pacific Coast from Humboldt County south to Sonoma County. Current distribution is fragmented and restricted to scattered locations within this range, primarily in coastal areas with suitable forest habitat. The species has been documented in coastal redwood forests, Douglas fir stands, and mixed coniferous forests from sea level to approximately 800 meters (2,600 feet) elevation. The species inhabits cool, moist coniferous forests with dense understory vegetation and substantial amounts of decaying woody debris. Microhabitat requirements include areas with fallen logs, dense shrub cover, and thick duff layers that provide protection from predators and temperature extremes. The voles construct elaborate runway systems through the forest floor litter and maintain multiple nest sites within rotting logs or under dense vegetation. California red-backed voles are primarily nocturnal and active year-round. Their diet consists mainly of fungi, particularly hypogeous fungi and mushrooms, supplemented by green vegetation, seeds, and occasionally small invertebrates. Breeding occurs from spring through fall, with females producing 2 to 4 litters per year. Litter size ranges from 2 to 6 young, with an average of 4 offspring. Gestation period is approximately 19 days, and young become independent at 3 to 4 weeks of age. The species exhibits high reproductive potential but also experiences high mortality rates typical of small rodents. While not federally listed, California red-backed voles face conservation challenges due to habitat loss and fragmentation. Logging activities, urban development, and forest management practices have reduced available habitat throughout their range. The species' dependence on old-growth forest characteristics, including large diameter fallen logs and complex forest floor structure, makes it particularly vulnerable to timber harvest and forest simplification. Climate change may also pose threats by altering precipitation patterns and temperature regimes in coastal forests. Population monitoring is limited, making it difficult to assess current population trends and conservation needs. The species serves as an indicator of forest ecosystem health and highlights the importance of maintaining structural complexity in coastal coniferous forests.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.