While studying wild gorillas in Rwanda last year, a team of vets observed something very exciting: a young female using a stick to forage for ants. While you may have heard of apes performing similar behaviors before, this is the first time that gorillas have ever been spotted using tools to acquire food in the wild.
Observing tool use in animals is exciting because it highlights similarities between humans and other members of the animal kingdom in terms of problem solving skills and dexterity. Although we now know that many different animals use tools, such as crows, dolphins and primates, prior to Jane Goodall’s observations of chimpanzees stripping the leaves off twigs and using them to dig out termites, it was believed that only humans made and used tools. It was this behaviour that scientists initially believed separated us from other animals, but we’ve known this is not the case for some 50 years now. So although this is a well-recognized behavior, it remains relatively rare.
The behavior was spotted by a team of vets studying a group of mountain gorillas residing in the Volcanoes National Park, Rwanda. The group has 23 members, including three silverback males, seven adult females, and several juveniles and infants. As described in the American Journal of Primatology, a male was seen sticking his hand into a hole in the ground in an attempt to catch ants for food. He quickly pulled it back out and ran away, presumably because he was bitten.
A female who had been watching the situation then approached the hole and repeated his actions. However, rather than accepting defeat, she picked up a nearby twig and used it to fish out ants which she then proceeded to munch on without being bitten.
Scientists are particularly interested in tool use in apes because it not only sheds light on the abilities of early humans, but also suggests that tool use may have its origins before the split between early humans and other ape lineages occurred. Chimpanzees have been observed making and using tools for a variety of purposes; such as fishing for termites, scooping out food and drinking. Scientists are also familiar with orang-utans using branches to forage for food, for example using poles to acquire fish from nets after watching humans spear fishing.
It was not until 2005 that the first observations of tool use in wild gorillas were made, when a female was spotted using a branch as a depth gauge before attempting to cross a pool of water. However, unlike other ape species, wild gorillas had never been seen using tools to eat prior to these latest observations.
While gorillas have been spotted using a range of tools in captivity for a variety of purposes, such as drinking, this behaviour has scarcely been observed in the wild. But this does not necessarily mean it is rare, as it could be due to a lack of studies. Furthermore, captive gorillas have less to do than wild gorillas and often have novel objects placed in their enclosures, both of which are likely to encourage experimentation.