Chimp Tool Selection May Reflect Early Hominin Strategies

WASHINGTON, D.C.—According to a Phys.org report, chimpanzees may choose tools for cracking nuts in a manner similar to that of early human ancestors. Some 2.5 million years ago, hominins used rocks to chop, scrape, and cut. Archaeological analysis of these tools indicates that the rocks were chosen for their properties, and that knowledge of these properties may have been passed down through generations. An international team of researchers led by D.R. Braun of The George Washington University and the Max Planck Institute for Evolutionary Anthropology provided chimpanzees with a selection of rocks with different properties, including elasticity, hardness, size, weight, and shape. The researchers determined that the chimps chose rocks based upon their mechanical properties—harder stones were used as hammers to smash nuts resting on softer stones employed as anvils. The scientists also found that younger chimps tended to choose tools that had already been used by their elders, perhaps as a way of learning established techniques. Read the original scholarly article about this research in Journal of Human Evolution. To read about a study that investigated hominins' hearing compared to that of chimpanzees and modern humans, go to "Neanderthal Hearing."