PUNISHMENT AS A FUNCTION OF AGGRESSION IN WILD CHIMPANZEES

My master thesis, supervised by Professor Klaus Zuberbühler and Professor Redouan Bshary, is a seven months study (September 2014-March 2015) on the chimpanzees of the Sonsocommunity at the Budongo Conservation Field Station , Uganda.

The first long-term studies on chimpanzees already documented the importance of aggressionin these animals. However, the function of some forms of aggression remains unclear. Here, I will focus on instances of aggression that could function as punishment. I will use the definition proposed by Clutton-Brock and Parker, i.e. that an individual pays a cost to inflict costs on another individual with the function to favourably alter the target's future behaviour. Until now it remains an open question whether wild chimpanzees indeed punish.

I will focus my observations on three contexts. First, chimpanzees often give food calls to attract group members to a site that offers high quality food. It has been described that individuals sometimes remain silent instead of calling.
Second, individuals greet each other when two parties join. However, greeting may be suppressed in the presence of a dominant who does not like to witness bonding between other group members. Third, females in oestrus often give copulation calls to inform other males about this activity but also may remain silent. In all three situations, aggression has been observed. The aim of this study is to find out if there is punishment in wild chimpanzees and to describe the settings in which it might occur, which may shed light on the evolution and function of punishment in our own species.