The chimpanzees were put into pairs, with one needed at the back and one at the front of a sealed plastic box. Through a hole the chimpanzee at the back had to push the grapes onto a platform using a rake. The chimpanzee at the front then had to use a thick stick and push it through a hole to tilt the platform so the grapes would fall to the floor and both could pick them up to eat.
One chimpanzee was handed both tools and they had to decide which tool to pass to the partner. Ten out of 12 individuals solved the task figuring out that they had to give one of the tools to their partner and in 73 per cent of the trials the chimpanzees chose the correct tool.
Dr Melis said: "There were great individual differences regarding how quickly they started transferring tools to their partner. However, after transferring a tool once, they subsequently transferred tools in 97 per cent of the trials and successfully worked together to get the grapes in 86 per cent of the trials.
"This study provides the first evidence that chimpanzees can pay attention to the partner's actions in a collaborative task, and shows they know their partner not only has to be there but perform a specific role if they are to succeed. It shows they can work strategically together just like humans do, working out that they not only need to work together but what roles each chimpanzee has to do in order to succeed.
"Although chimpanzees are generally very competitive when trying to gain access to food and would rather work alone and monopolize all the food rewards, this study shows that they are willing and able to strategically support the partner performing their role when
|Contact: Kelly Parkes-Harrison|
University of Warwick