Ancient Chimps Used Stone Hammers to Crack Nuts.

Scientists discovered that ancient chimpanzees used stone tools to crack nuts 4,300 years ago.

The excavated stones showed the hallmarks of use as tools for smashing nuts when compared with ancient human or modern chimpanzee stone tools.

The use of stone tools may have a deep evolutionary origin
Also, several types of starch grains were found on the stones, which the researchers say is residue derived from cracking local nuts.

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