Monkeys make their mark

摘要

Wild monkeys leave behind long-lasting traces of their efforts to crack nuts with tools - evidence that could be useful to archaeologists. Bearded capuchin monkeys (Sapajus libidinosus, pictured) open seeds such as palm nuts by placing them on stone and wood surfaces, or anvils', and then pounding them with rocks. Elisabetta Visalberghi at the Institute of Cognitive Sciences and Technologies in Rome and her colleagues tracked this behaviour every month for three years at a study site in Brazil. The monkeys left behind tell-tale pits on the surfaces, and the discarded nut shells remained strewn around the anvils for years. The animals also moved stone hammers to use them at other anvils. The physical records left by modern monkeys create archaeological signatures that could help researchers to study tool use among ancient monkeys and early humans.