An important paper in Current Anthropology on the evolution of cooperation in carnivores. When we look at at the origins of cooperation in humans, we tend to focus on primates (not surprisingly) or we look at Everything (a.k.a. evolution of society), including bacteria, insects etc.
Here is s fascinating view of another, non-primate branch of the tree, a branch which is not that far, and might have much more to do with human evolution (and the effect of hunting and intergroup conflict) that we might have expected.
Here is the paper:
Smith, J. E., Swanson, E. M., Reed, D., & Holekamp, K. E. (2012). Evolution of Cooperation among Mammalian Carnivores and Its Relevance to Hominin Evolution. Current Anthropology