Life-history patterns in female wild boars (Sus scrofa): mother–daughter postweaning associations

Abstract

Mother–daughter postweaning associations in wild boars (Sus scrofa L., 1758) were investigated using 12 years' data from a wild population in Champagne, France. In the wild boar, a polygynous ungulate species, females (i) can reproduce as soon as they are yearlings and (ii) generally have large litters, in contrast to many other ungulate species. It is generally thought that their social organization is centered around groups of adult females and their offspring, but genealogical relationships in female groups have never been studied. Hence this species is suitable for testing the hypothesis of a matrilineal social organization. We studied the occurrence and strength of mother–daughter associations before and after the first potential breeding of yearling females, using a total of 85 individuals. Seasonal fluctuations in associations were observed, but after weaning, daughters generally remained with the mother. When leaving their natal group, yearling females formed new kin groups with sisters. Two important factors involved in the postweaning associations were adult and yearling reproductive participation and maternal age. The present study constitutes the first clear demonstration that family groups, with overlapping generations of females, represent the typical social organization in a forest wild boar population.