Remarkable video clips of wild chimpanzees using "tool kits" to dig out termites from an underground nest have been recorded by scientists, who believe it is the most sophisticated culture yet observed in great apes.
Although chimps are known to use long twigs as simple tools to fish for termites - a nutritious delicacy - it is the first time that a far more complex behaviour involving two different kinds of tools has been observed in the wild.
Crickette Sanz, of the Max Planck Institute in Leipzig, and David Morgan, of Cambridge University, made the video with the help of hidden cameras trained on termite mounds in the tropical forests of the Congo that chimps are known to frequent.
They filmed the chimps, who were using a thick stick which they had prepared by stripping its leaves, to push a tunnel a foot deep in to the heart of the nest. Once they had removed the stick, they pushed a far more delicate twig that had been deliberately frayed at one end down the tunnel and into the heart of the nest, said Professor Andrew Whiten, of Edinburgh University.
"These chimpanzees use something that doesn't happen anywhere else. They use a tool kit. They left one part of the tool kit, which is a big strong stick, at the termite nest," he told the American Association for the Advancement of Science in St Louis. "They'll pick it up and push it right down into the ground. What they are doing is inserting it to make a tunnel into the termite's subterranean nest.
"They use their hands and their foot to dig down, so they look like Mr McGregor with his spade digging down with great effort. We don't understand how possibly they could have worked out how to do that," he said.
The next stage involves pulling the stick out, discarding it and using another, flimsier twig with a frayed end, which they push down the tunnel to fish for termites that crawl on to the twig. The twig is then used as a feeding utensil.
Professor Whiten said the remarkable behaviour was passed on between members of the same troop as a cultural tradition unique to that group of animals. He said it is one of more than 40 different behaviours scientists have observed in wild chimps that are culturally inherited by young animals.
Research has shown that such behaviour varies across Africa, with chimps in the west displaying significantly different cultural traditions to chimps in the east. "Those difference in behaviour have all the hallmarks of being traditions. We've discovered that there are many of them and they are really rich in variety," he told the meeting.
"In far west Africa, chimps use stones and branches to crack nuts. That's really important to them. But chimps don't do that in east Africa. And even more important, in west Africa they don't do it on the east side of a major river."Reuse content