Macaca sylvanus

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.

Abstract: Examined were 5 years of data on the reproduction of a semifree-ranging population of Barbary macaques (Macaca sylvanus). In this seasonally breeding species – birth season: mid-Mar

Abstract: It has long been shown that the social environment of individuals can have strong effects on health, well-being, and longevity in a wide range of species. Several recent studies found that an individual’s number of affiliative partners positively relates to its probability of survival. Here, we build on these previous results to test how both affiliation and aggression networks predict Barbary macaque (Macaca sylvanus) survival in a “natural experiment.” Thirty out of 47 wild Barbary macaques, living in 2 groups, died during an exceptionally cold winter in the Middle Atlas Mountains, Morocco. We analyzed the affiliation and aggression networks of both groups in the 6 months before the occurrences of these deaths, to assess which aspects of their social relationships enhanced individual survivorship. Using only the affiliation network, we found that network clustering was highly predictive of individual survival probability. Using only the aggression network, we found that individual survival probability increased with a higher number of aggression partners and lower clustering coefficient. Interestingly, when both affiliation and aggression networks were considered together, only parameters from the aggression network were included into the best model predicting individual survival. Aggressive relationships might serve to stabilize affiliative social relationships, thereby positively impacting on individual survival during times of extreme weather conditions. Overall, our findings support the view that aggressive social interactions are extremely important for individual well-being and fitness.

Abstract: The Barbary macaque (Macaca sylvanus) is the earliest offshoot of the genus Macaca and the only extant African representative, all other species being Asiatic. Once distributed throughout North Africa, M. sylvanus is now restricted to isolated forest fragments in Algeria and Morocco. The species is threatened; the maximum total wild population size is estimated at 10,000 individuals. Relationships among surviving wild subpopulations in Algeria (96 samples) and Morocco (116 samples) were examined by using 468-bp sequences from hypervariable region I of the mitochondrial DNA control region. Twenty-four different haplotypes were identified, differing by 1-26 mutational steps (0.2-5.6%) and 1 insertion. With one exception (attributable to secondary introduction in coastal Morocco), Algerian and Moroccan haplotypes are clearly distinct. However, whereas Moroccan subpopulations show little divergence in hypervariable region I sequences and little correspondence with geographical distribution, there is a deep division between two main subpopulations in Algeria and one marked secondary division, with haplotypes generally matching geographical distribution. Accepting an origin of the genus Macaca of 5.5 million years ago, the Moroccan population and the two main Algerian subpopulations diverged ≈1.6 million years ago. Distinction between Moroccan and Algerian haplotypes permitted analysis of the origin of the Gibraltar colony of Barbary macaques (68 samples; 30% of the population). It is generally held that the present Gibraltar population descended from a dozen individuals imported during World War II. However, the Gibraltar sample was found to include Algerian and Moroccan haplotypes separated by at least 16 mutational steps, revealing a dual origin of the founding females.