Incremental dentin and associated enamel, features visible at the surface of lower incisors of rodents, may chronicle important life-history information. This study investigated surface features of lower incisors representing 4 taxa of prairie dogs (Cynomys) in relation to hibernation and season of year. A set of abnormalities in dentin and enamel, observed on 20 of 138 incisors, always chronicled an event ending in late winter or early spring and was interpreted as a hibernation mark. Hibernation was recorded in the incisors of obligate hibernators, C. leucurus and C. gunnisoni, as well as in 20% of specimens of the facultative heterotherm, C. ludovicianus, with relevant winter growth record. Inspection of prairie dog incisors from museum collections elucidated patterns in the timing of spring emergence across species, sexes, and elevations. Growth rates of prairie dog incisors (estimated from thicknesses of circadian dentin increments) showed general seasonal patterns when pooled by sex and species, but daily growth rates recorded along individual incisors often fluctuated idiosyncratically through time. However, incisors that chronicled a significant temporal trend in daily growth rate registered either early-season (increased growth rate through time) or late-season growth (decreased growth rate through time). None of 11 late-Pleistocene fossil C. niobrarius churcherii exhibited a hibernation mark, but 4 of these exhibited significant decrease in growth rate along their incisors, probably indicating animals that died late in the active season.