The gray-tailed vole, Microtus canicaudus, also known as the gray-tailed meadow vole and the gray-tailed meadow mouse, is a rodent in the genus Microtus, which are small eared "meadow voles" of the family Cricetidae. First collected in 1895, it is endemic to the Willamette Valley, Oregon and Clark County, Washington in the Pacific Northwest region of North America. Voles are small mammals and the gray-tailed vole is considered medium sized among voles. Historically, they were found among the prairies of the valley. They remain common, while much of these areas have been converted for agricultural purposes. For unclear reasons, populations densities of voles in an area may widely fluctuate from season to season and year to year. They are preyed upon by owls, hawks, and carnivorous mammals. Parasites include fleas and ticks. They build underground burrows and complex tunnel networks, sometimes shared with other burrowing animals in their area. Relatively little is known about their behavior in the wild, because they are elusive and unlikely to enter traps.