Duration of Gestation and Lactation for Gunnison's Prairie Dogs

The length of gestation is the number of days between fertilization and parturition, and the length of lactation is the number of days between parturition and weaning. Determination of these lengths is difficult for ground-dwelling squirrels such as prairie dogs, marmots, and ground squirrels that usually copulate, give birth, and nurse offspring underground. For Gunnison's prairie dogs ( Cynomys gunnisoni ), the mean ±1 SD length of gestation is 29.3 ± 0.53 days ( n = 124). The approximate length of lactation, estimated from the mean ± 1 duration between parturition and the first emergence of juveniles from the natal burrow, is 38.6 ± 2.08 days ( n = 112).