Prairie dog and Clark in 1804. Lewis described it in more detail in 1806, calling it the "barking squirrel". On average, these stout-bodied rodents will grow to be between long, including the short tail, and weigh between . Sexual dimorphism in body mass in the prairie dog varies 105 to 136% between the sexes. Among the species, black-tailed prairie dogs tend to be the least sexually dimorphic, and white-tailed prairie dogs tend to be the most sexually dimorphic. Sexual dimorphism peaks during weaning, when the females lose weight and the males start eating more, and is at its lowest when the females
Gunnison's prairie dog females. Gunnison's prairie dogs have 22 teeth, and five pairs of mammary glands. The Gunnison's prairie dog, "C. gunnisoni", is the only prairie dog species that has 40 chromosomes. The other four species, black-tailed, white-tailed, Utah, and Mexican prairie dogs, have 50 chromosomes. Their coats are yellow-toned buff merged with black-colored hairs. The upper head, sides of the cheek, and eyebrows are distinctly darker than the rest of the body. Their tails are mostly white with grayish-white ends and the tips are light gray. The Gunnison's prairie dogs go through two yearly periodic moults during spring and fall. In spring,