Gunnison's prairie dog is a member of the Sciuridae family, which includes squirrels, chipmunks, marmots, and prairie dogs. Gunnison’s prairie dog (Cynomys gunnisoni) adults vary in length from 309 to 373 millimeters (12 to 15 inches) and weigh 650 to 1,200 grams (23 to 42 ounces), with males averaging slightly larger than females. The dorsal color is yellowish buff intermixed with blackish hairs. The top of the head, sides of cheeks, and “eyebrows” are noticeably darker than the dorsum. The species differs from black-tailed prairie dogs (C. ludivicianus) in having a much shorter and lighter colored tail, and from white-tailed prairie dogs (C. leucurus) and Utah prairie dogs (C. parvidens) in having grayish-white hairs in the distal half of the tail rather than pure white. The Gunnison’s prairie dog has sometimes been divided into two subspecies: Cynomys gunnisoni gunnisoni and C. g. zuniensis. The USFWS currently regards the Gunnison’s prairie dog as a single species because the most recent published analyses do not support subspecies designation. However, ongoing genetic analyses suggests past geographic isolation, followed by limited mixing in regions coincident with the recognized borders of the two purported subspecies. Although analyses are still ongoing, there is increasing evidence for Gunnison’s prairie dog subspecies designation. The USFWS will reevaluate the subspecies designation issue when the final genetics report that includes data from the entire species range is completed.