The Prairie Dog Template
The prairie dog (Cynomys spp.), a rodent of the squirrel family (Sciuridae), is a colonial burrowing mammal restricted to western North America. The most well-known species to zoo-visitors and casual naturalists is the black-tailed prairie dog (C. ludovicianus), but there are four other species currently described: the Mexican (C. mexicanus), white-tailed (C. leucurus), Utah (C. parvidens), and Gunnison’s (C. gunnisoni). Prairie dogs are further subdivided into the black-tail group (consisting of the black-tailed and Mexican species) and the white-tail group (consisting of the white-tailed, Utah, and Gunnison's species).
Prairie dogs are ground squirrels and are diurnal (daytime active), colonial (with varying degrees of colony and ward density), fossorial (built for and dependent on burrowing), herbivorous rodents found in varied grassland ecosystems (from the great plains to high-elevation mountain valleys).
Species ludovicianus | mexicanus | leucurus | parvidens | gunnisoni
“In morphology and appearance, the species are remarkably similar. Excluding the tail, adults of all species are 25 to 40 centimeters long. Color of the fur ranges from yellowish to reddish to dark brown…Standing adults are distinctly pear-shaped, and adult body mass varies from 300-900 grams in spring to 500-1,500 grams in late summer and early fall…”
“White-tails, utahs, and gunnisons all have short tails—30 to 65 millimeters and less than 20% of the total body length—with a variable amount of white or gray hair. They hibernate for several months of each year, and live in mid- or high-grass meadows at altitudes of 1,700 to 3,000 meters. Mexicans and black-tails have longer tails—60 to 110 millimeters and more than 20% of the total body length—with a distinct black tip, do not hibernate, and live in low-grass prairies at altitudes of 700 to 1,700 meters.”
- The Black-tailed Prairie Dog, J.L. Hoogland, 1995
While all prairie dog (PD) species share a common template in regards to physiology, biology, ecology, and behavior, there are both subtle as well as stark differences among them, especially between the black-tail group and the white-tail group. For example:
- the black-tail species do not hibernate; the white-tail species do
- the black-tailed PD performs a well-known "jump-yip" call that is absent in all other species
- the black-tailed and Utah PDs participate in allogrooming (grooming each other) while the other species do not
- infanticide is common in black-tailed and Utah PDs, and rare in the others
- alarm calls and territorial calls differ in pattern and sometimes posture among the species
- and more...
Understanding the similarities and differences among species is what has driven John and other researchers through decades of study on this iconic animal.
Above we have a side-by-side of a white-tailed prairie dog (left) and a Gunnison's prairie dog (right). Both are part of the white-tail group, and would be near impossible to tell apart if not for geography.
The five species are found in distinct regions, and can easily be identified geographically. The most wide-ranging species is the black-tailed prairie dog, a conspicuous presence in the grasslands of Montana, the Dakotas, Nebraska, Kansas, Oklahoma, and Texas. The black-tailed can also be found in eastern Wyoming, eastern Colorado, eastern and southern New Mexico, and less commonly in southeast Arizona. The white-tailed prairie dog range extends through central and southern Wyoming, northeast Utah, and northwest Colorado. The Utah prairie dog is found in a more limited range in central and southwest Utah only. And the Gunnison’s prairie dog is described as a four corners species, found where Colorado, New Mexico, Arizona, and Utah meet, extending through a good portion of each of those states, especially New Mexico and Arizona. The Mexican prairie dog, being the least common and least studied, is found in a small geographic range in northcentral Mexico.
All prairie dog species live in grassland habitats, but these habitats can be varied. The white-tail group (white-tailed, Utah, and Gunnison’s) are typically found at higher elevations than the black-tail group (black-tailed and Mexican): 5500-9500 feet elevation versus 2300-7220 feet respectively. – taken from The Utah Prairie Dog: Life Among the Red Rocks by Theodore G. Manno.
Prairie dogs prefer to live in prairies with relatively low vegetation, and of course much of that low vegetation is a result of the prairie dogs themselves selectively foraging on a variety of species of grass, brush, cactus, flowers and seeds, and thistle. Occasionally an insect or worm will be consumed, and roadkill carrion will be opportunistically fed on – not to mention the rare meat that is eaten during cannibalizing events (see our page on INFANTICIDE for more on that).
Grasslands, as the name suggests, are dominated by grasses but are also home to brush, sedge, flowering plants, some woody plants, and occasionally trees. Grasslands may be found at a variety of altitudes and they support a wide array of wildlife from insects to megafauna. Prairie dogs play a key role in these ecosystems (see CONSERVATION), and are mutually dependent on grasslands.
The western United States is a four-season region, with variations in winter conditions at different latitudes and altitudes. All species in the white-tail group spend their winter in deep torpor underground, but the black-tailed and Mexican prairie dogs do not hibernate in any part of their range. Less is known about the Mexican PD, but the black-tail group remains active (though less so on especially cold days) throughout the winter. Regardless of the species, it is important that prairie dogs put on as much weight as possible before winter, to either survive hibernation or to survive overwintering. Those prairie dogs who hibernate go into a deep torpor, lowering their body temperatures and metabolic processes; they may experience occasional wakefulness while in their burrows, but are not expected aboveground again until the mating season nears in the spring and the prairie becomes habitable again. As for non-hibernators, the extra fat gained in the spring and summer will carry them through scarce times as forage becomes buried under snow or is lost to frost.
Snowfall is common throughout the prairie dog range in the American west, and may still be falling sporadically in the early spring as the mating season approaches and hibernating species are emerging from their torpor. The harsh conditions can be taxing, and many prairie dogs (especially the smaller juveniles) will have already died over the winter, but by March the survivors are generally safe from fatally inclement conditions barring occasional spring snowstorms. Prairie dogs keep their thicker winter coat (which they gained during their second molt in the early fall) through the early months of spring.