Lemmiscus curtatus
sagebrush vole

Lemmiscus curtatus is found in the western United States and Canada, primarily in the Great Basin and Great Plains regions. Its range extends from southern Saskatchewan and Alberta to northern Colorado, to the west coast of the United States. (Nowak, 1999)

Sagebrush voles inhabit areas largely dominated by bunch grasses and sagebrush. Semi-arid prairies, brushy canyons, and rolling hills with loose soil are preferred habitats. (Nowak, 1999)

Pelage is pale gray and buff dorsally, with silver, white, and buff ventrally. Their fur is dense and is usually longer and softer than that of Microtus. Head and body length is usually 90 to130 mm, and tail length ranges from 16 to30 mm. Body weight is between 17 to 38 grams. Their body appears to be stocky. Adaptations for burrowing in loose soil are haired palms and soles, short tail, stout claws, and small ears. (Nowak, 1999)

See Reproduction.

Reports regarding the mating system of this species are variable. The weight of evidence seems to support the conclusion that sagebrush voles are monogamous.

Mullican and Keller (1986) reported that these animals live in male-female pairs in the wild, indicating a monogamous existence. One captive study confirmed that males and females share a single nest during the post-partum period, as is common for monogamous microtine rodents (Hofmann, et al., 1989). In species known to be polygynandrous, males inhabit separate nests. Also, in their breeding colony, pups often continued to inhabit the parental nest when another litter was born. This supports the notion that local concentrations of animals seen in the wild represent extended families, living in a somewhat colonial fashion.

However, not all of the data collected by Hofmann, et al (1989) were consistent with a monogamous breeding system. They also showed that males and females did not coordinate their activity to ensure that at least one parent was always with the pups, as has been reported for monogamous species. Further, males spent very little time caring for the pups, which is uncommon for monogamous species, and is very common in polygynous species. Further research is needed to clarify the mating system of this rodent.

Sagebrush voles breed year round, although in the northern portion of their range they generally breed only from March to early December. The estrous cycle of sagebrush voles is approximately 20 days, and within 24 hours after giving birth, a postpartum estrus occurs. A litter of 5 is average, with a range from 1 to 13. Gestation usually lasts between 24 to 25 days. Captive members of this species have been known to produce 14 litters in one year, but in the wild average 2 to 3 litters per year. Females in the wild may live together while raising young, or males and females may nest together.

Young are born naked and blind in an underground nest chamber composed of leaves, shredded sagebrush bark, and grass stems. At birth, young weigh approximately 1.5 grams. They open their eyes at 11 days, and by 21 days they are usually self-sufficient. (Brylski and Harris, 2001; Nowak, 1999)

Males may be aggressive, particularly during breeding. Sexual maturity for females is reached around 60 days, and for males between 60 and 75 days. (Brylski and Harris 2001; Hofmann et al. 1989; Nowak, 1999) (Brylski and Harris, 2001; Hofmann, et al., 1989; Nowak, 1999)

The young are altricial. In captivity, both male and female care for the young. Because males and females have been reported to nest together in the wild (Mullican and Keller, 1986), this probably occurs in wild populations also. Hofmann, et al. (1989) showed that females generally spent more time alone in th nest than did males. They also groomed pups more frequently than did males. Frequency of grooming the pups decreased as the pups aged. (Hofmann, et al., 1989; Mullican and Keller, 1986)

Information on lifespan in L. curtatus is not available. However, other voles are known to live an average of less than one month (Microtus pennsylvanicus) to a maximum in captivity of nearly four years (M. guentheri). (Nowak, 1999)

Sagebrush voles are active year round, and throughout the day. Their peak periods of activity are from 2-3 hours before sunset to 2-3 hours after complete darkness, and 1-2 hours before and after sunrise. They either occur in pairs or are solitary, and despite conflicting opinions, are not known to be colonial. They establish burrows in clusters that usually have 8-30 entrances each, and are often hidden by cover. Many short tunnels at depths of 80-460mm occur within the network of burrows, and a nest chamber can be 250mm in diameter. Tunnels abandoned by pocket gophers are often integrated into the network of burrows. Sagebrush voles use surface runways and short adjacent tunnels that act as escape holes. They often have a series of burrow networks and will switch networks depending on food availability. (Mullican and Keller, 1986; Nowak, 1999)

Sagebrush voles are herbivores, and feed upon the flowers and fleshy parts of vegetation, but not the seeds. Newly harvested vegetation may be piled before it is consumed, and it is often brought into burrows. There is no evidence of food caching in this species. They often forage under shrub canopy and grass cover, and may climb in to shrubs to feed. They are also known to steal from other individual’s food piles. (Brylski and Harris, 2001; Mullican and Keller, 1986; Nowak, 1999)

Predators include owls, hawks, snakes, coyotes, bobcats, and badgers. (Brylski and Harris, 2001)

Sagebrush voles may evade predators by burrowing, restricting activity to locations under vegetation, remaining cryptic, and by living in colonies or extended families.

Sagebrush voles are important food for a variety of predatory species.

This species is not known to directly benefit humans. However, as a prey species, sagebrush voles provide food for charismatic megafauna.

No negative interactions with humans have been reported in the literature.

Population densities of 4-16 per hectare have been found in southeastern Idaho. Demographic patterns of Lemmiscus are different when compared to vole species that experience annual or multiannual population fluctuations. Much of the original range of sagebrush voles has been altered as a result of agriculture and overgrazing. (Brylski and Harris, 2001; Mullican and Keller, 1986; Nowak, 1999)