Nut-cracking Brazilian monkeys could teach us about human evolution

Human beings were always defined as the “tool-maker species.” But our domination over this important skill was brought into question in the 1960s when renowned anthropologist Jane Goodall discovered that chimpanzees will pick and modify stems of grass in order to use them to collect termites. Her findings challenged Homo sapiens’ very place in the biological order. Since Dr. Goodall’s research, scientists’ knowledge of tool use by animals has expanded exponentially. We now know that monkeys, crows, parrots, pigs, and many other animals can use tools, and research on animal tool use has changed our understanding of how animals think and learn. Studying this process of animals using tools may also provide clues to solve the mysteries of human evolution.

Our human ancestors’ shift to making and using tools is linked to evolutionary changes in hand anatomy, a transition to walking upright, and increased brain size. But using found stones as pounding tools doesn’t require any of these advanced evolutionary traits, in fact, it likely came about before humans began to manufacture tools. By studying this percussive tool use in monkeys, researchers such as my colleagues and I can infer how early human ancestors practiced the same skills before the evolution of hands, posture, and brains.

Monkeys using tools

Understanding the memory, thinking, and problem-solving abilities of wild animals is unsurprisingly difficult. In experimental research where animals are asked to perform a behavior or solve a problem, there should be no distractions, such as the threat of predation....