Just like humans, horses can have tooth problems that make them ornery and sap their productivity. So to keep their horses in top shape, Mongolian herders started experimenting with equine dentistry more than 3,000 years ago, according to new archaeological evidence published today in the Proceedings of the National Academy of Sciences.

Through an analysis of skulls excavated from ancient horse burials on the Mongolian steppe, funded in part by a grant from the National Geographic Society, archaeologists determined that nomads initially sawed off their horses’ unruly teeth with stone tools, and, later, pulled teeth that got in the way of metal mouthpieces.

These “incredible innovations” in horse healthcare “came right alongside what looks like the emergence of horse riding,”