Polygynandrous and repeated mounting behaviour in European badgers, Meles meles

Promiscuous and repeated mountings by females are evolutionarily intriguing as females are expected to be choosy and matings are expected to be costly. We evaluate the evolutionary basis of these behaviours in a high-density population of European badgers. We analysed postpartum mounting behaviour, in 3 years, at two neighbouring social groups each year. We demonstrate a polygynandrous social mating system, with repeated mounting. Mounting was skewed among females in four social-group-years, but overall did not differ from random, potentially because female reproductive success is context dependent, varying with local food availability and female–female competition. Some males mounted more than others; however, male mounting frequency was not related to dominance rank, self-grooming rate, or body condition index. Mounting frequency did not predict paternity success; furthermore, a 16-year genetic data set showed that paternity success was positively correlated with body condition index. Females may therefore mount with males that do not father their offspring to minimize the risk of infanticide from them. Females may also trade mountings for allogrooming from males, but mounting frequency did not vary with relatedness, aggression received from males or sequential allomarking by males. We conclude that promiscuous and repeated mounting in badgers may have evolved to reduce male–male aggression around mounting and the likelihood of infanticide from males by masking paternity. Promiscuous mounting of female badgers does not devalue the previous male’s sperm, but may promote sperm competition, genetic diversity and genetic compatibility.