Male chimps choosy about allies
Male chimps are quite choosy about forming coalitions when it comes to siring offspring, especially in keeping aggressive rivals at bay.
A new study by Ian Gilby at Duke University in North Carolina and his colleagues has further revealed that it may not just be the coalition that is important but who the coalition is with that determines future success.
Their study finds that male chimpanzees with central positions in the coalitionary network were most likely to father offspring and increase in rank.
Specifically, those who formed coalitions with males who did not form coalitions with each other were the most successful, the journal Behavioral Ecology and Sociobiology reports.
The most dominant males are more likely to mate and therefore, sire offspring. Males with high coalition rates are more likely to mate more often than expected for their rank, according to a Duke statement.
Coalitionary aggression is when at least two individuals jointly direct aggression at one or more targets. Aggression and coalition formation between males is important for attaining a higher dominance in many animal species.
Gilby and his colleagues studied data from wild chimpanzees gathered over 14 years from the Kasekela community in Gombe National Park in Tanzania.
"Our data suggests that there are consequences to the recognition of third-party relationships. As such, it represents an important step toward a more complete understanding of the adaptive value of social intelligence and the evolution of cooperation," say the study authors.