Cutting edge: An equine inquiry

Studying abnormalities in the vertebrae of ancient skeletons could help Marsha Levine to date the earliest domestication of the horse

Before the development of firearms, horses were crucial to warfare, and before the invention of the steam engine, they were the fastest and most reliable form of land transport. Today their importance in the undeveloped and developing world has scarcely diminished. But despite intensive investigations over many years, researchers know very little about the origins and evolution of horse husbandry and the osteological consequences of riding and traction.

For a long time, it was believed that the earliest origins of horse domestication dated to the Eneolithic period at a Ukrainian settlement site called Dereivka (c. 4,000-4,500BC). Later, another Eneolithic settlement site, Botai in northern Kazakhstan (c. 3,500BC), was also connected with early horse domestication. However, the evidence presented as proof for domestication at these sites is seriously flawed. Probably the main argument was the apparent widespread increase in the quantity of horse bones and teeth recovered from Eneolithic central Eurasian archaeological sites (c. 4,800-3,000BC) by comparison with those from the preceding Neolithic period (c. 6,000-4,800BC). This argument depends on the theory that horses became extinct throughout most of Europe at the end of the Ice Age, but that did not happen. Horses may not have been as abundant then, but they were widespread throughout Eurasia during the early post-glacial period. The apparent increase in the frequencies of horse bones and teeth during the Eneolithic period is better explained by increased hunting rather than by the introduction of herding.

The earliest evidence for horse domestication - datable textual and artistic evidence as well as archaeological remains of horses with humans in chariot burials - probably dates back only to the end of the third millennium BC. However, it seems likely that horse husbandry would have developed prior to its earliest manifestations in art and burial ritual, and it seems probable that horses were first domesticated for riding. So what is the earliest evidence of horse riding?

Palaeopathological analysis, the study of ancient pathology, is proving to be one of the most promising approaches for investigating the origins of horse domestication. Recent research indicates that certain abnormalities of the caudal thoracic vertebrae - the vertebrae below the saddle - could be connected with riding. Four Early Iron Age Scytho-Siberian skeletons from the Ak-Alakha 5 site, in the Altai Mountains, Russia, dated 5th to 3rd century BC, were found buried with bits between their teeth. All of them have similar abnormalities of the caudal thoracic vertebrae, suggesting they were horses used for riding.

The initial results of comparisons of the Early Iron Age horses, which wore pad saddles, with free-living modern Exmoor Ponies, which were never saddled, and with medieval Turkic horses, found at the Ak-Alakha 1 site, which wore frame saddles, strongly suggest that these abnormalities are associated with the use of pad saddles and, most probably, with riding bareback. Furthermore, these types of abnormalities are entirely absent from the sample of caudal thoracic vertebrae I studied from the Eneolithic site at Botai. This suggests that the bones came from horses that had never been ridden.

The next step will be to compare the osteological abnormalities of draught horses with those of riding horses and free-living horses. Professor Li Shuicheng from the Arthur M. Sackler Museum of Art and Archaeology at Peking University has invited me to study 47 skeletons from chariot burials belonging to four periods: the Shang dynasty, the Western Zhou dynasty, the Warring States period and the Qin dynasty.

Marsha Levine is a researcher at the McDonald Institute for Archaeological Research, Cambridge.