Use of tools is one of the measures of intelligence. When human ancestors started using tools, they began developing their intellectual capabilities at an unprecedented pace. However, humans are not the only ones using tools for thousands of years. Scientists from UCL say that bearded capuchins have been employing stone tools for around 3,000 years.
Capuchin monkeys are so-called New World monkeys, because they live in Central America and South America as far south as northern Argentina. They reach a length of 30 to 56 cm, have small heads and long tails. They are not something you would expect great intelligence from, but scientists found that capuchin monkeys at Serra da Capivara National Park in Brazil have been using stone tools for processing a variety of food types over at least the past 3,000 years. What’s even more interesting is that these tools evolved over time too, improving in efficiency and design.
Several groups of capuchin monkeys live in The Serra da Capivara National Park in Brazil and all of them are capable of using stone tools. They use them to dig, crack nuts, crush seeds, process fruits and even bang them together in a display of sexuality. It is quite interesting that capuchins choose stones for a specific task. For example, they choose rounded quartzite cobbles and use them as hammers, while various roots and other rocks take the role of the anvil.
Scientists focused on an open-air site within Serra da Capivara National Park, where capuchins are known for cracking and eating cashew nuts. Researchers found 122 identifiable capuchin stone artefacts, mostly old rocks previously used as hammers. Scientists employed methods known in archeology, such as radiocarbon dating and stone tool analysis, and found that these tools come from approximately 3,000 – 2,400 years ago. Although the basic principles remained the same, capuchin tools evolved over time, became more efficient and easy to use.
Dr Tomos Proffitt, one of the authors of the study, said: “this study contributes to a growing understanding that other animals also possess an identifiable archaeological record and an ancient material culture. The identification of the world’s oldest monkey stone tools contributes to the growing field of primate archaeology and goes to show that humans might not be as unique as we once thought”.
The next step for researchers will be describing the evolution of capuchin tools. The next step for capuchins, however, is to learn to make tools. Collecting rocks from the ground and using them is smart, but not as smart as actually making the tools by yourself.