Some stone tools attributed to prehistoric humans may in fact have been made by horse

"Some stone tools attributed to prehistoric humans may in fact have been made by horses, according to researchers in Spain.

Horses kick and stamp on rocks to keep their hooves in good shape, and archaeologists have now realised this can result in a collection of sharp stones that look like the work of an ancient human toolmaker"

https://www.newscientist.com/article...t-human-tools/