Solitary Ethiopian wolves increase predation success on rodents when among grazing gelada monkey herds

Abstract

Mixed-species associations generally form to increase foraging success or to aid in the detection and deterrence of predators. While mixed-species associations are common among mammals, those involving carnivorous predators and potential prey species are seldom reported. On the Guassa Plateau, in the Ethiopian highlands, we observed solitary Ethiopian wolves (Canis simensis) foraging for rodents among grazing gelada monkey (Theropithecus gelada) herds. The tolerant and sometimes prolonged (> 1h) associations contrasted with the defensive behaviors exhibited by geladas toward other potential predators. Ethiopian wolves spent a higher proportion of time foraging and preyed more successfully on rodents when among geladas than when alone, providing evidence that gelada herds increase the vulnerability of subterranean rodents to predation. Ethiopian wolves appear to habituate gelada herds to their presence through nonthreatening behavior, thereby foregoing opportunistic foraging opportunities upon vulnerable juvenile geladas in order to feed more effectively on rodents. For Ethiopian wolves, establishing proximity to geladas as foraging commensals could be an adaptive strategy to elevate foraging success. The novel dynamics documented here shed light on the ecological circumstances that contribute to the stability of mixed groups of predators and potential prey.