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A team of primatologists observed in Congo-Brazzaville a world first in gorillas: striking with bare hands. Monkeys, our cousins, are able to use many tools.
It’s a gesture that may seem trivial to you: hitting two stones against each other. But it’s less so when it comes to gorillas. This is a world first observed by a team of scientists led by primatologist Shelly Masi in the Nouabalé-Ndoki National Park in Congo-Brazzaville. Their finding was published last month in review Nature and provides additional insight into tool use by monkeys.
It is a discovery almost by chance. By studying the diet of gorillas in the natural environment, in this case the Congolese forest, the primatologists realized that two young gorillas were using a novel technique to feed on termites. “ Instead of hitting a piece of termite mound against the hand to get the termites out, and eating them, they took two pieces of termite mound, one in each hand, before hitting them together, says Shelly Massy, who works for the National Museum of Natural History and the Musée de l’Homme in Paris. We call that “strikes it with bare hands”. »
Stone Age
After striking with bare hands, in the history of humanity, our ancestors then acquired “percussion striking”, the ability to produce shards of stone, to make tools, weapons…” It is a key gesture in the evolution of humanity “Says Shelly Masi. Human beings then entered the Stone Age, a decisive stage in their conquest of the planet. So, when two monkeys perform the strike with their bare hands, is this small gesture of the hand a big step for the humanity of the gorillas? No, it is not tomorrow the day before that the largest African ape will pass into the Stone Age like its human cousins. ” It would take thousands of years of evolution “says Shelly Masi.
The use of tools in gorillas has also been rarely observed, for a reason that jumps out in an animal that can weigh up to 250 kilos. ” They are the biggest apes that exist, so they use their strength and power more to destroy. It’s not a cognitive limit, it’s just that they don’t need to. The smaller chimpanzees, for example, use the fine technique of “the fishing rod” to enter the termite mounds and “to fish” termites. »
The chimpanzee toolbox
Chimpanzees, our closest cousins, use about forty tools. In Senegal, to hunt, they make sharp spears by chewing on the end of a branch. They also use natural sponge to collect water. But not all chimpanzees use the same tools. ” Ivory Coast chimpanzees use stones to crack nuts. Chimpanzees in Uganda have the same nuts, the same stones in the forest, but do not use the stones to crack the nuts; we think it’s really a different culture. »
Scientists have found that genetic inheritance does not interfere with tool use, at least in mammals. ” When a gesture is effective, other individuals can observe this gesture, see that it has advantages, and therefore copy it, explains Shelly Masi. This will be the basis for the development of a culture. There can therefore be what is called social learning by imitation of another individual. »
Doctor monkeys
Primates have many tools to their bow. For example, orangutans and gorillas have been observed crossing a river with the help of a stick, to see if they have feet, as a human would. In Gabon, scientists have seen chimpanzees, again them, catch a flying insect and apply it to a wound, which demonstrates ” the ability to understand that this insect can possibly release analgesic substances for the wound. There are other examples in chimpanzees using leaves and applying them to wounds. », says Shelly Masi. Here the tool is a leaf or an insect and the monkey a doctor.
“Only monkeys use tools in the animal world?” »
No, tool use has been observed in over a hundred species of animals. The birds are particularly skilful, like the crows, very intelligent, able to make a hook with a wire to catch food or to drop a nut on the road, so that the wheels of a car break the hull; when the light turns red, the crow lands on the road and goes to eat the nut. The cockatoo drums it with a stick to attract the female. Among insects, let us cite the case of a caterpillar that makes a kind of shelter with a cut-out leaf to be able to nibble on its meal out of sight of predators. Among mammals, dolphins protect their snout with a sponge so as not to injure themselves while searching the seabed. But back to our monkeys, definitely full of resources: orangutans use pieces of wood to masturbate.