Equine tooth extractions evolved to make way for a riding bit, making mounted warfare possible
Mongolian pastoralists were trying to remove troublesome teeth from horses’ mouths almost 3,200 years ago, making those mobile herders the earliest known practitioners of horse dentistry, a new study finds.
Those initial, incomplete tooth removals led to procedures for extracting forward-positioned cheek teeth known as first premolars from young horses, say archaeologist William Taylor and his colleagues. That dental practice, which dates to as early as about 2,800 years ago, coincided with the appearance in Mongolia of metal bits that made it easier for riders to control horses, the researchers report the week of July 2 in the Proceedings of the National Academy of Sciences. Long-distance travel and mounted warfare with sedentary civilizations across Asia soon followed (SN: 11/25/17, p. 16).
“Veterinary dentistry was instrumental in the rise of horse warfare on the Eurasian steppes, allowing herders to use metal bits while avoiding behavior and health complications for horses that may have accompanied bit use,” says Taylor, of the Max Planck Institute for the Science of Human History in Jena, Germany. In particular, first premolars could interfere with a bit’s movement and cause pain or damage to the tooth.
Taylor’s group identified microscopic signs of cutting and sawing on frontal teeth from two of 10 Bronze Age Mongolian horses. These two teeth, which date to between around 3,200 and 2,900 years ago, apparently grew at odd angles that may have interfered with chewing. Horseback riding became widespread in Mongolia at that time (SN: 5/27/17, p. 10).
Of seven Mongolian horses dating to between around 2,800 and 1,650 years ago that had empty first premolar jaw sockets, six displayed bone regrowth in those sockets indicating that teeth had been extracted or lost due to other causes before the animals died.
Tooth be gone
Evidence of first premolar extraction appeared in an empty tooth socket, right (black arrow), of a Mongolian horse from between around 2,300 and 2,700 years ago. A Mongolian horse from roughly 3,000 years ago, left, retains its first premolar (white arrow), indicating that the dental procedure was not yet in use.
W.T.T. Taylor et al. Origins of equine dentistry. Proceedings of the National Academy of Sciences. Published online the week of July 2, 2018. doi:10.1073/pnas.1721189115.
B. Bower. How ancient nomadic herders built new Bronze Age cultures. Science News. Vol. 192, November 25, 2017, p. 16.
T.H. Saey. Ancient DNA bucks tale of how the horse was tamed. Science News. Vol. 191, May 27, 2017, p. 10.