1. ECOS
2. Species Profile for Utah prairie dog (Cynomys parvidens)

Utah prairie dog (Cynomys parvidens)

Listing Status:   

Where Listed: WHEREVER FOUND

General Information

Prairie dogs belong to the Sciuridae family of rodents, which also includes squirrels, chipmunks, and marmots. There are five species of prairie dogs, all of which are native to North America and all of which have non-overlapping geographic ranges (Hoogland 1995; Hoogland 2003). Taxonomically, prairie dogs are divided into two subgenera (Hoogland 1995): white-tailed and black-tailed. The Utah prairie dog is a member of the white-tailed group, subgenus Leucocrossuromys. Other members of this group, which also occur in Utah, are the white-tailed prairie dog (Cynomys leucurus) and the Gunnison prairie dog (Cynomys gunnisoni). The Utah prairie dog is widely recognized as a distinct species (Zeveloff 1988; Hoogland 1995). The Utah prairie dog is most closely related to the white-tailed prairie dog. These two species may have once belonged to a single interbreeding species (Pizzimenti 1975), but they are now separated by ecological and physiographic barriers. The type locality for the Utah prairie dog is Buckskin Valley in Iron County, Utah (Pizzimenti and Collier 1975, p. 1). Genetic variance within Utah prairie dog populations is very low – less than half that commonly observed for black tailed prairie dogs (Chesser 1984; Ritchie and Brown 2005)). This may be the result of genetic drift in small populations (Chesser 1984). The Utah prairie dog’s color is cinnamon to dark buffy cinnamon mixed with small amounts of buff or blackish hairs. This species can be distinguished from the two other white-tailed species by a black spot above the eye (Pizzimenti and Collier 1975), a brown cheek patch, the cinnamon to clay coloration of the dorsum and the proximal half of the tail, and the all-white terminal half of the tail (Hollister 1916). However, color alone is not considered a reliable tool to differentiate between prairie dog species (Hoogland 2003). Adult Utah prairie dogs range in total body length from 250 to 400 mm (9.8 to 15.7 in.) including a tail length of 30 to 65 mm (1.2 to 2.6 in.) (Hollister 1916; Hoogland 1995). Adult males weigh between 750 and 1,410 grams (g) (1.7 to 3.1 pounds (lbs)) and adult females weigh between 640 to 1,140 g (1.4 to 2.5 lbs) (Wright Smith 1978). Body weight varies by sex and season. For example, in spring, male body mass ranges from 300 to 900 g (0.7 to 2 lbs) but by late summer or early fall, their body mass ranges from 500 to 1500 g (1.1 to 3.3 lbs) (Hoogland 1995).

• States/US Territories in which the Utah prairie dog, Wherever found is known to or is believed to occur:  Utah
• US Counties in which the Utah prairie dog, Wherever found is known to or is believed to occur:  View All

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No critical habitat rules have been published for the Utah prairie dog.

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Habitat Requirements

Utah prairie dogs prefer swale-type formations where moist herbaceous vegetation is available even during drought periods (Collier 1975; Crocker-Bedford 1976; Crocker-Bedford and Spillett 1981). Plentiful food and other resources enable prairie dogs to attain large body mass, thus enhancing survival and reproduction (Hoogland 2001). Soil characteristics are an important factor in the location of Utah prairie dog colonies (Collier 1975; Turner 1979; McDonald 1993). Well-drained soils are a habitat requirement for Utah prairie dogs burrows, and burrows must be deep enough (at least 3.3 ft (1 m)) to protect the prairie dogs from predators and environmental and temperature extremes. Soil color may aid in disguising prairie dogs from surface predators and thus may be an added survival factor. Utah prairie dogs generally avoid areas where brushy species dominate, and will eventually decline or disappear in areas invaded by brush (Collier 1975; Player and Urness 1983). Vegetation on prairie dog colonies is of short stature to allow the prairie dogs to see approaching predators and have visual contact with other members of the colony (Collier 1975; Crocker-Bedford and Spillett 1981; Player and Urness 1983). However, we have observed Utah prairie dogs occupying pine fir forests in Bryce Canyon National Park. As a keystone species, prairie dogs have a large effect on the ecosystem. Prairie dogs decrease vegetation height and increase landscape heterogeneity. Burrowing and excavation mixes the soil and promotes uptake of nitrogen by plants (Whicker and Detling 1993 in Miller et al. 2000; Hoogland 2001). The burrow and mound systems change soil chemistry by increasing the porosity of the soil to allow deep penetration of precipitation, and increasing the incorporation of organic materials into the soil (Munn 1993 in Miller et al. 2000). Several wildlife species such as burrowing owls (Athene cunicularia), rabbits (Lepus spp.), ground squirrels (Spermophilus spp.), weasels (Mustela spp), and badgers (Taxidea taxus) also rely on the habitat conditions created by Utah prairie dog colonies, and frequently utilize their burrows (Collier and Spillett 1975; Hoogland 2001).

Food Habits

Utah prairie dogs are predominantly herbivores, though they also eat insects, primarily cicadas (Cicadidae) (Crocker-Bedford and Spillett 1981; Hoogland 2003). tGrasses are a staple of the annual diet (Crocker-Bedford and Spillett 1981; Hasenyager 1984), but other plants are selected during different times of the year. Utah prairie dogs only select shrubs when they are in flower, and then only eat the flowers (Crocker-Bedford and Spillett 1981). Forbs are consumed in the spring, and there is a preference for alfalfa over grasses when both are present (Crocker-Bedford and Spillett 1981). This is important because many agricultural fields within the range of the prairie dog are planted in alfalfa crops – for example, Iron County (i.e., West Desert RU) was ranked second highest producing for alfalfa in the state (USU 2005). Forbs may also be critical to prairie dog survival during drought (Collier 1975). Prairie dogs discriminate between particular plant parts when feeding. Flowers and seeds are selected and preferred when they are available, and young leaves are selected over old leaves (Crocker-Bedford and Spillett 1981; Hasenyager 1984). Stems rarely are eaten (Crocker-Bedford and Spillett 1981). Utah prairie dogs eat almost all the green vegetation they cut, and by selecting flowers, seeds, and young leaves, they obtain high amounts of proteins and digestible energy. Vegetation quality and quantity are important in helping Utah prairie dogs survive hibernation, lactation, and other high nutrient demand times (Environmental Defense 2007). Plant species richness is correlated with increased weight gain, higher juvenile to adult ratios, and higher animal densities (Crocker-Bedford and Spillett 1981; Ritchie and Cheng 2001).

Movement / Home Range

Utah prairie dogs are organized into social groups called clans, consisting of an adult male, several adult females, and their offspring (Wright-Smith 1978). Clans maintain geographic territorial boundaries although they will use common feeding grounds. Utah prairie dogs spend approximately 59 percent of their time feeding, 25 percent of their time in alert behavior, including predator watch and intruder monitoring, 2 percent of their time in social interactions between clan members, and the remainder of their time in various activities such as grooming, digging and burrow maintenance, and inactivity (Wright Smith 1978). Natal dispersal (movement of first year animals away from their area of birth) and breeding dispersal (emigration of a sexually mature individual from the area where it copulated) are male biased, which leads to the loss of young males from a colony and higher mortality through predation (Hoogland 2003). Young male Utah prairie dogs disperse in the late summer with average dispersal events of 0.35 mi (0.56 km), long-distance dispersal events of up to 0.75 mi (1.2 km), and unusually long-distance dispersals of 1.1 mi (1.7 km) (Crocker-Bedford 1976; Mackley 1988). We believe some rare dispersal events may exceed these documented distances.

Reproductive Strategy

Mating begins soon after female emergence from hibernation in late February or early March (Hoogland 2003). Female Utah prairie dogs come into estrous and are sexually receptive for only several hours on one day during the breeding season (generally mid-March through early April) (Hoogland 2001). Consequently, female prairie dogs wean a maximum of one litter per year. All female Utah prairie dogs copulate, but only two-thirds wean a litter (Hoogland 2001). Utah prairie dog reproduction and survival are influenced by the availability of food and other resources. Adult females require twice as much energy during the lactation period than at other times of the year (Crocker-Bedford and Spillett 1981). Litter size varies directly with maternal body mass (Hoogland 2001). Heavy adult males are more likely to copulate and thus sire more offspring than lighter males (Hoogland 2001). Litter size ranges from 1 to 7 pups and mean litter size is 3.88 pups (Pizzimenti and Collier 1975; Wright-Smith 1978; Hoogland 2001). The young emerge from their nursery burrow when they are 5 or 6 weeks old after a gestation period of 30 days. The young attain adult size by October and reach sexual maturity at the age of 1 year (Wright Smith 1978).

Other

Utah prairie dogs hibernate by spending four to six months underground each year during the harsh winter months, although they are occasionally seen sunning themselves on days with mild weather (Hoogland 2001). Adult males cease surface activity during August and September, and females follow suit several weeks later; lactating females enter hibernation later than non lactating females (Hoogland 2003). Juvenile prairie dogs remain above ground 1 to 2 months longer than adults and usually hibernate by late November. Adult females and juveniles likely go into hibernation later because they need more fat stores for hibernating than adult males do (McDonald 1993). Utah prairie dogs emerge from hibernation in late February or early March, with males emerging 2 to 3 weeks prior to females (Hoogland 2003). Utah prairie dogs are subject to natural predation by coyotes (Canis latrans), badgers (Taxidea taxis), long-tailed weasels (Mustela frenata), various raptor species, and Great Basin rattlesnakes (Crotalus oreganus lutosus) (USFWS 1991; Hoogland 2001). In established colonies, predators probably do not exert a controlling influence on numbers of prairie dogs (Collier and Spillett 1972). Utah prairie dogs also are subject to natural competition with several species of ground squirrels, which can have population-level effects, such as competitive interactions impacting distributional patterns (Collier and Spillett 1975). Utah prairie dog populations are susceptible to sylvatic plague (Yersinia pestis), a bacterium introduced to the North American continent in the late 1800’s (Cully 1993). There is a limited understanding of the variables that determine when sylvatic plague will impact prairie dog populations (see section 1.7.3, Plague). Fleas are the vectors that spread the disease and can be brought into the vicinity of a prairie dog colony by a suite of mammals (Biggins and Kosoy 2001). Plague outbreaks generally occur when populations increase to high densities causing increased stress among individuals and easier transmission of disease between individuals (Gage and Kosoy 2005).

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