Female/Female Competition in European Badgers Meles meles: Effects on Breeding Success

Abstract

We present data on the effects of female/female competition on the reproductive success of European badgers Meles meles in Britain. While a single, dominant female usually suppresses reproduction in other female group members, elsewhere up to four females may breed successfully in each group. Across Britain, the mean number of breeding females per social group decreases in populations living at high latitudes, where food availability and population density are relatively low. Within our study population in southern England, the number of breeding females in each social group increased with the quality of the group territory. In our study population, all females aged 3 years and older became pregnant, but a proportion of females lost their litters during gestation or around the time of birth. The proportion of females that lost their litters was higher in larger groups. However, mean litter size at weaning remained roughly constant despite variation in the number of females lactating, and preweaning cub mortality appeared to be low. Females tended to disperse away from very large groups, and may have increased their chances of breeding in this way. These results suggest that females competed for breeding status, but that there was little competition among females thereafter. The characteristics of females that produced cubs successfully differed between the 2 years when this study was carried out. Only females in relatively good condition bred successfully following a very dry summer, when food availability was low. However, when food availability was high, following a wet summer, females were in better condition on average and breeding success appeared to be related to social status. We suggest that this reflected a difference in the structure of competition between the two years. In contrast with the situation in other social carnivores, reproductive suppression in badgers appears to be a response to female/female competition for resources, rather than a need for co-operative care of the young. Although alloparental care occurred in at least one badger population, this population had the lowest, rather than the highest, level of reproductive suppression.