Male lions in large coalitions gain reproductive advantages

Cooperation between two or more individuals has been shown to yield short-term benefits in several vertebrate species1–4, and various hypotheses have been developed to explain the evolution of cooperative behaviour5–7. However, until now there has been no evidence to show that such cooperation actually does confer lifetime's reproductive advantages on more than one member of the coalitions concerned8,9. Long-term studies of wild lions (Panthera leo L.) have now provided such evidence. We show that, compared with singletons and pairs, male lions in groups of three or more can more reliably gain tenure of female prides, retain tenure for longer, mate with more different females, and produce more surviving offspring; thus each individual has higher fitness through cooperation.