Abstract

We report the death of 30 wild Barbary macaques, living in two groups, during
an exceptionally cold and snowy winter in the Middle Atlas Mountains,
Morocco.We examined whether an individual’s time spent feeding, the quality
and number of its social relationships, sex and rank predicted whether it survived
the winter or not. The time an individual spent feeding and the number
of social relationships that an individual had in the group were positive and significant
predictors of survival. This is the first study to show that the degree of
sociality affects an individual’s chance of survival following extreme environmental
conditions. Our findings support the view that sociality is directly
related to an individual’s fitness, and that factors promoting the establishment
and maintenance of social relationships are favoured by natural selection.