Origins of equine dentistry.

From the American West to the steppes of Eurasia, the domestic horse transformed human societies, providing rapid transport, communication, and military power, and serving as an important subsistence animal. Because of the importance of oral equipment for horse riding, dentistry is an essential component of modern horse care. In the open grasslands of northeast Asia, horses remain the primary form of transport for many herders. Although free-range grazing on gritty forage mitigates many equine dental issues, contemporary Mongolian horsemen nonetheless practice some forms of dentistry, including the removal of problematic deciduous teeth and the vestigial first premolar ("wolf tooth"). Here, we present archaezoological data from equine skeletal remains spanning the past 3,200 y, indicating that nomadic dental practices have great antiquity. Anthropogenic modifications to malerupted deciduous central incisors in young horses from the Late Bronze Age demonstrate their attempted removal, coinciding with the local innovation or adoption of horseback riding and the florescence of Mongolian pastoral society. Horse specimens from this period show no evidence of first premolar removal, which we first identify in specimens dating to 750 BCE. The onset of premolar extraction parallels the archaeological appearance of jointed bronze and iron bits, suggesting that this technological shift prompted innovations in dentistry that improved horse health and horse control. These discoveries provide the earliest directly dated evidence for veterinary dentistry, and suggest that innovations in equine care by nomadic peoples 1150 BCE enabled the use of horses for increasingly sophisticated mounted riding and warfare.