Why do female prairie dogs copulate with more than one male?—Insights from long-term research

Abstract

Abstract A female usually obtains sufficient sperm to fertilize all her eggs from a single insemination, and mating can be costly. Yet, paradoxically, polyandry (i.e., copulation with 2 or more males) is common among organisms of all types, from amoebae through humans. Research that spanned 35 years shows that females of 3 species of prairie dogs benefited from polyandry by rearing more yearlings (a component of fitness that is my best estimate of female reproductive success); females of a 4th species (the black-tailed prairie dog [Cynomys ludovicianus]) evidently did not benefit from polyandry. Reasons for the higher production of yearlings by polyandrous females differed among species. For Gunnison's prairie dogs (C. gunnisoni), 3 other components of fitness contributed to the higher production of yearlings: a higher probability of conception and parturition, larger litter size at weaning, and a higher survivorship of offspring during the first 9 months after weaning. The 2nd and 3rd components applied ...