A team from Oxford and the University of São Paulo in Brazil, found the earliest archaeological examples of monkey tool use outside of Africa. The research raises questions as to the origins and spread of tool use in New World monkeys and whether early human behaviour was influenced by observing monkeys using stones as tools.
The researchers observed groups of modern capuchins at Serra da Capivara National Park in northeast Brazil, and combined this with archaeological data from the same site. The team watched wild capuchins use stones as hand-held hammers and anvils to pound open hard foods such as seeds and cashew nuts. Young monkeys learned from older ones. The capuchins created what is described as, ‘recognisable cashew processing sites.’ They left stone tools in piles at specific places like the base of cashew trees or on tree branches after use. These capuchins also specifically chose tools that were most suitable for the task.
From an archeological standpoint, researchers excavated 69 stones to understand whether and how this tool technology had developed at all over time. The tools were identified by inspecting the size and shape of the stones, and the damage on the stone surface which was attributed to capuchin pounding. Through mass spectrometry, the researchers were able to confirm that dark-coloured residues on the tools were specifically from cashew nuts. With carbon dating, they established the oldest were least 600 to 700 years old.
Based on their data, the team estimated that around 100 generations of capuchins used the tradition of stone tools. They found a lack of change over hundreds of years, with similar materials seen in the excavated examples and the tools used by modern capuchins.
The study presents evidence that primates who lived outside Africa used tools. This is an unexplored area of scientific study that may even tell us about the possible influence of monkeys’ tool use on human behavior.
The paper, Pre-Columbian monkey tools, is published in the latest issue of Current Biology.
For more information, visit: http://www.ox.ac.uk/