Humans on Horseback
New evidence on domestication of horses—and the spread of an ancient Eurasian culture
Throughout much of Eurasia, a single pastoralist culture that thrived between 4,000 and 5,000 years ago left behind an indelible genetic imprint still detectable in modern populations from India to Russia to Western Europe. How could a band of animal herders centered on the grassy steppe north of the Caspian Sea have expanded its influence so dramatically? A leading theory, eloquently articulated by David Anthony in his 2007 book, The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World, points to the domestication of the horse—as well as the invention of the wheel—as possible enablers of an astounding episode of human migration by the Yamnaya people. Now, that hypothesis is backed by new information.
While linguistic and archaeological evidence provides support for Yamnaya herding and milking of horses, whether they also rode them has remained unproven. A new study of ancient human skeletal remains detects morphological evidence of horseback riding in the bones of individuals from the Yamnaya culture—the earliest known traces of human horseback riding. The research was led by anthropologists at the University of Helsinki, together with colleagues from Romania, Bulgaria, Hungary, Poland, and the United States. David Anthony, who in 1989 began studying museum collections of Yamnaya skeletal remains in the Soviet Union, is a co-author of the research, and the sole North American anthropologist on the team. A professor emeritus at Hartwick College, and an associate of Harvard’s department of human evolutionary biology, he has been collaborating in retirement on genetic studies of the Yamnaya people and their origins with professor of genetics and of human evolutionary biology David Reich (for more about Reich, Anthony, and the Yamnaya people, see the feature profile, “Telling Humanity’s Story through DNA”).
Previous research has clearly established the importance of horses in the Yamnaya culture. Some of their kurgans—timber-lined graves covered with raised mounds of earth—even contain the bones of horses. And analysis of peptides in dental calculus accreted on the teeth of Yamnaya individuals reveals that they also drank the milk of horses. But scientific evidence that they also rode them has been missing.
The researchers identified six osteological deformations that are characteristic of people who habitually ride horses, from impingements of the hip caused by sitting with the legs apart, to reshaping of leg bones, to degeneration of the vertebrae. Evidence of traumas that frequently befall horsemen—fractures caused by falls or kicks, bites to the hands, injuries caused by a horse stepping on a foot—were also considered. In all, the researchers identified six skeletal traits associated with horseback riding, and assessed 217 ancient individuals from 39 sites west of the Black Sea.
The anthropologists developed a rating system, in which a cluster of these traits were deemed likely to be indicative of horseback riding. Their approach, they note, has limitations: many of the skeletons are incomplete (with an average completeness of 57 percent), meaning that some evidence of riding may be missing in many individuals, potentially understating the prevalence of horsemanship. And some of the deformations associated with “horseback-riding syndrome,” according to the authors, can also be caused by occupational forces and disease, which could lead to misclassification of potential riders.
Nevertheless, when four or more such traits appear in a single individual, the researchers believe, horseback riding is a plausible explanation.
Given the known spread of Yamnaya genes during the Bronze Age, the researchers emphasize their discovery that five geographically dispersed individuals, spanning almost the entire duration of the Yamnaya culture, appear to have been habitual horseback riders. This is the first biological evidence of this innovation, which by enabling mass migration of these pastoral nomads, is likely to have been a crucial element in the economic and reproductive success of the Yamnaya.
Mass migration as an explanation for cultural change fell out of favor after World War II, Anthony explained in a 2022 interview in which he spoke about his continuing research into horseback riding. Economic, political, and religious explanations for cultural change predominated beginning with the “new archaeology” that arose in the 1960s. But Anthony argued that mass migration as an explanation for cultural change should not be completely dismissed. His 1990 paper, “Migration in Archaeology: The Baby and the Bathwater” is one of his most cited. Still, what the new genetic evidence has shown—a massive spread of Yamnaya genes from the Eurasian steppe in every direction—went far beyond what even Anthony was contemplating as possible in the ancient world.
“It really looks like the Yamnaya people invented pastoral nomadism, the most mobile form of economy that humans practice,” he said. “It is the kind of economy that was practiced by the Huns and the Mongols in Central Asia and before that, by the Scythians”—all better known successors to the Yamnaya’s nomadic lifestyle.
The question, he explained, has always been, “When did that kind of economy get invented? It’s a very complicated way to live.” Anthony suspects that horseback riding was already being practiced when wheeled wagons first appeared after about 5,500 years ago. “Those two things together made it possible have a mobile way of life. Essentially, the wagons carried all of the heavy things that humans need: water, food, clothing, protection from the elements. And horses were used for control of very large herds and for rapid travel.” Though horses were later used in warfare by successor cultures to the Yamnaya, Anthony believes that the earliest importance of horseback riding was to make herding much more efficient, thus expanding the compass of “the mobile way of life that the Yamnaya people invented.”