The archaeological record of human tools use dates back about 2.5 million years, and archaeologists use changes in stone tool technology to trace changes in human evolution, culture, and lifestyles. Now a team of archaeologists in Brazil has excavated capuchin monkey stone tools dating back to 3,000 years ago, and they reveal changes in behavior and diet over thousands of years—just like the early human archaeological record but on a compressed time scale.
Archaeology: not just for humans
Bearded capuchin monkeys are more versatile tool-users than chimpanzees. They select rocks of the right sizes and shapes for a variety of tasks, from digging to cracking open a range of nuts and seeds (each has its own size and weight specifications for the perfect cracking tool). Female capuchins even flirt with potential mates by throwing rocks at them.
At Brazil’s Serra de Capivara National Park, a group of capuchins crack open cashews with round quartzite cobbles, which they choose and carry to the cashew grove from a dry streambed about 25m (82 feet) away. Capuchins have been processing their food at the same spot for at least 3,000 years—and leaving behind their distinctively banged-up tools. That’s about 450 monkey generations, and during that time, archaeologists noticed some major changes in the stone hammers and how they were used.