In 2007 it was reported that chimps at Fongoli, Senegal were hunting with tools. Scientists were sufficiently impressed with that finding but less accepting of the idea that it was predominantly female chimps using the tools.
Jill Pruetz who conducted the original study found in both significant and interesting but many researchers dismissed the idea due to the small sample size. However, Pruetz and her research team have continued continued to research the topic in the years since the initial report and now have a much more substantial sample size.
In research published in Royal Society Open Source, the researchers report with much greater emphasis that female chimps are more likely to use tools.
Overall male chimps made up 60 percent of all hunting groups but females made up 60 percent of hunters using tools. In 305 documented case of hunting with tools, the tools were used by females 175 times. Male were far more likely to capture prey by hand.
“It’s just another example of diversity in chimp behavior that we keep finding the longer we study wild chimps. It is more the exception than the rule that you’ll find some sort of different behavior, even though we’ve studied chimps extensively,” said Pruetz in a statement.
The primary prey of this group of chimps, in tool assisted hunts, was bush babies. According to the researchers, the chimps would find the animals hiding in tree cavities and use a “spear-like” tool to stab at them.
According to Pruetz, one of the possible explanations for the difference in hunting strategies is that the male chimps are more opportunistic.
“What would often happen is the male would be in the vicinity of another chimp hunting with a tool, often a female, and the bush baby was able to escape the female and the male grabbed the bush baby as it fled,” she said.
The population of savanna chimps at Fangoli are the only chimp population and the only non-human population known to consistently hut using tools.
Pruetz believes that the anomaly may reflect a social tolerance among the Fangoli group that does not exist in other chimpanzee populations.
“At Fongoli, when a female or low-ranking male captures something, they’re allowed to keep it and eat it. At other sites, the alpha male or other dominant male will come along and take the prey. So there’s little benefit of hunting for females, if another chimp is just going to take their prey item,” she said.
Environment and prey could also be factors. According to the researcher, the preferred prey of chimps at other sites are red colobus monkeys. The Fongoli site has few monkeys and the bush babies lend themselves to hunting with tools.
Protease also notes that she is frequently asked why the chimps tool use is considered hunting rather than gathering. Termite or ant fishing, for example, is considered gathering.
“Fishing for termites is a very different activity than jabbing for a bush baby. With fishing, termites grab on to a twig and don’t let go and the chimp eats the termites off the twig. When hunting, the bush baby tries to bite, escape or hide from the chimp. The chimps are really averse to being bitten by a bush baby,” said Pruetz.
Bush babies are not as fierce as monkeys but, according to Pruetz, it is no different from humans hunting doves instead of deer.
