A female can usually obtain enough sperm to fertilize all her eggs from a single insemination, and copulation involves certain costs such as increased exposure to diseases and parasites. Why, then, do females of so many species routinely copulate with more than one male? A 7-year study of marked individuals provides an answer for 239 female Gunnison's prairie dogs (Sciuridae:Cynomys gunnisoni) living under natural conditions. The probability of pregnancy and parturition was 92% for females that copulated with only one or two males, but was 100% for females that copulated with at least three males. Further, litter size at weaning varied directly with the mother's number of sexual partners. Published in Animal Behaviour,...
At a colony of Gunnison's prairie dogs, Sciuridae:Cynomys gunnisoni, containing marked individuals of known genetic relationships, anti-predator calling was investigated in response to moving, stuffed specimens of a natural predator, the American badger,Taxidea taxus. Females with kin in the home territory called more often than females without nearby kin, and females with nearby offspring were especially likely to call. Male gunnisons commonly gave anti-predator calls as well, but male calling was unrelated to kinship of nearby listeners. 1996 The Association for the Study of Animal Behaviour Published in Animal Behaviour, volume 51, issue 4, on pages 871 - 880, in 1996.