Humans and chimpanzees are not the only primates to use tools. South American capuchin monkeys have developed a sophisticated system for cracking nuts, and new research shows that they’ve been at it for hundreds, if not thousands of years – and suggests they might even have taught humans a trick or two.
In 2004 the bearded capuchin became the first species of monkey documented to use tools in the wild, though the behaviour was already well known to local people.
These intelligent little primates use stone hammers to crack open cashew nuts placed upon large, flat rock anvils. Both tools are carefully selected for the job and are carried or dragged to cashew stands, often from afar.
Excavations of one such ‘cashew factory’ in Brazil’s Serra da Capivara National Park are now providing a tantalising glimpse into the behaviour.
Biologists and archaeologists, led by Michael Haslam of the University of Oxford, have unearthed similar tool kits in deposits laid down at least 700 years ago. But they suspect that the practice is much older.
“It has probably been happening for several thousand years, after some capuchin species migrated to more open areas where they could use the ground,” said Haslam’s colleague Tiago Falótico.
Strikingly, the technology seems to have changed little over seven centuries – a period that has seen remarkable progress in human culture. It might be the case, though, that the monkeys contributed to our own successes.
“This is an exciting, unexplored area of scientific study that may even tell us about the possible influence of monkeys’ tool use on human behaviour,” said Haslam. “For example, cashew nuts are native to this area of Brazil, and it is possible that the first humans to arrive here learned about this unknown food through watching the monkeys’ industry.”
So while some great apes have shown the capacity to take from human culture, added Falótico, this may be a rare example of the learning process flowing the other way.
Source Current Biology.
Main image: The stones used by capuchins as hammers can weigh over 1kg, though the monkeys themselves weigh less than 4kg © Mike Lane/iStock