Contexts and Patterns of Injuries in Free-Ranging Male Baboons (Papio Cynocephalus)

AbstractInjury in male baboons (Papio cynocephalus) was investigated as an indicator of damaging fights in order to provide a framework for analyses of conflict resolution and dynamics of agonistic competition in primates. The vast majority of wounds were canine slashes resulting from intraspecific face-to-face combat. Wounds were more common in males than females. In males they concentrated on the right side of anterior parts of the body, principally the head. Wounds took on average three weeks to heal. Aggressive conflicts represented 10% of all interactions between males. Less than 1% of aggressive contests led to injury. The individual rate of injury from fights with other males was on average once every 1.5 months. The winner of damaging fights was sometimes the wounded individual. The number of wounds per damaging fight was not related in a simple way to the presence of proceptive females or to recent immigration events. Four fights yielding the highest number of injuries, however, involved recent immigrations or attempts to immigrate by adult males in their prime. Contexts of male injury observed during infliction include challenges to the resident alpha male by newcomers, intertroop encounter, fights over proceptive females or unusual foods, redirected aggression, defense of a female and a fight unrelated to any obvious resource. This study and anecdotal reports from the literature point at various implications of injury to male baboons, including physical impairments which can constrain feeding efficiency, limit access to resting sites and safe retreats, cause a drop in dominance rank, jeopardize mating success and even result in death. Severely injured males typically reduce interaction rates, retreat to the periphery of the troop or emigrate temporarily. Although most wounds are small and heal well, the potentially high costs of injury probably exercise strong selection pressure on contestants for means of peaceful conflict resolution, given that during fights both baboons risk injury irrespective of their competitive abilities. The potential fitness consequences of inflicted injury can explain the evolution of the formidable canine weaponry of some male primates.