Cooperation is rare in animals, yet in species such as the African lion cooperation permeates all aspects of their lives. Cooperation is only expected to occur where animals associate persistently with their close kin, or where social interactions result in mutual benefit to each participant. Gaining a full understanding of the evolution of cooperation therefore requires information on the precise ways that cooperation is elicited, the distribution of cooperative acts among companions of varying degrees of kinship and the effects of such cooperation on the participants' lifetime reproductive success. Many different kinds of cooperative behavior in lions can be elicited by playing the recorded roars of intruders in their territories. In the next three years the investigators will perform playbacks both where the willingness of an individual to cooperate is visible to its companions and where its behavior would be unseen. Several other forms of cooperation will also be investigated under natural conditions. The consequences of cooperative behavior in these lions can be estimated from the 22 years of demographic data available on the study populations. These studies provide a unique opportunity to learn how animals have evolved complex forms of cooperative behavior. The long term demographic data will also be used to develop detailed models of lion population dynamics. These will be used to simulate the fates of populations of varying sizes and to calculate the potential impact of human disturbances on natural populations.
