Tracing the Origins of Horseback Riding: Insights from Human Skeletons

Reexamining the Kurgan Hypothesis through Ancient Skeletal Analysis

A new study¹ challenges long-held beliefs about the origins of horseback riding, casting doubt on the Kurgan hypothesis, which claims that humans first began domesticating horses as early as the fourth millennium B.C. Archaeologists from the University of Colorado Boulder have explored the skeletal remains of ancient humans, shedding light on whether physical changes in bones can definitively reveal the early use of horses for transportation.

Can Horseback Riding Change Your Skeleton?

Horseback riding can indeed leave subtle marks on the human body. The study, conducted by archaeologists, utilized evidence from medical studies of modern equestrians and examined human remains spanning thousands of years. Their findings suggest that activities like horseback riding can influence skeletal structures, particularly in the hip joint, where the ball and socket may become elongated over time. However, the researchers caution that this type of skeletal change is not exclusive to riding; other activities, such as prolonged sitting or riding in carts, can also produce similar alterations.

Skeletal Evidence: Complicated but Inconclusive

According to Lauren Hosek, lead author of the study and an assistant professor at CU Boulder, identifying a specific activity based solely on skeletal changes is a complex task. Hosek said,

“In archaeology, there are vanishingly few instances in which we can tie a particular activity unequivocally to skeletal changes.”

This statement highlights the difficulties in interpreting bone alterations as evidence of horseback riding alone.

A monument dedicated to renowned racehorses stands in Arvaikheer, Mongolia. Archaeologist William Taylor has investigated the origins of horse domestication at various sites across the Mongolian steppe. (Credit: William Taylor)

Published in Science Advances, the study introduces an important layer of skepticism regarding the use of skeletal remains to date the advent of horse domestication, a pivotal question in archaeology.

The Debate over the First Equestrians: Revisiting the Kurgan Hypothesis

The question of when humans first began riding horses has long been a topic of debate. William Taylor, co-author of the study and curator of archaeology at the CU Museum of Natural History, explained that the earliest definitive evidence of humans using horses for transport comes from the region near the Ural Mountains, dating back approximately 4,000 years. Artifacts such as bridles and chariots from this period provide concrete evidence of horse domestication.

However, the Kurgan hypothesis, formulated in the early 20th century, claims that the domestication of horses began much earlier, around 3500 B.C., in a culture known as the Yamnaya. This group is thought to have lived near the Black Sea and spread their culture and language as they rode on horseback across Eurasia. The theory links the spread of early Indo-European languages to horse domestication. Taylor noted, emphasizing the importance of accurately dating this transformative event in human history,

“A lot of our understanding of both the ancient and modern worlds hinges on when people started using horses for transportation.”

Can Hips Tell the Full Story?

The new research casts doubt on the skeletal evidence used to support the Kurgan hypothesis. Hosek explained that changes in the shape of the hip joint, which some researchers have used as evidence for early horseback riding, can result from various activities. For instance, the repetitive pressure caused by sitting in a flexed position, such as riding in a cart or carriage, can also lead to similar changes. Hosek said,

"Over time, this repetitive, intense pressure from that kind of jostling in a flexed position could cause skeletal changes.”

This makes it difficult to draw definitive conclusions from skeletal remains alone.

Notably, evidence from western Asia shows that humans used cattle, donkeys, and wild asses for transport long before horses were domesticated. Ancient peoples likely used these animals to pull carts, contributing to the same kinds of skeletal changes seen in human remains.

The Limits of Skeletal Analysis

While the study acknowledges that skeletal changes can provide clues about ancient human behavior, Hosek and Taylor argue that human remains alone cannot be used to establish when people first began riding horses. The researchers call for a more holistic approach to the study of early horse domestication, integrating genetic data and archaeological evidence from horse remains. Hosek emphasized,

“Human skeletons alone are not going to be enough evidence. We need to couple that data with evidence coming out of genetics and archaeology and by looking at horse remains, too.”

What This Means for the Kurgan Hypothesis

The findings do not support the Kurgan hypothesis as strongly as once thought. Despite claims that the Yamnaya people domesticated horses around 3500 B.C., the skeletal evidence is far from conclusive. According to Taylor,

"At least for now, none of these lines of evidence suggest that the Yamnaya people had domestic horses."

The study challenges traditional narratives about the relationship between humans and horses, opening the door for further investigation into when and where horse domestication first began. It also emphasizes the need for interdisciplinary research to paint a more accurate picture of human history.

The Kurgan hypothesis suggests that the Yamnaya culture expanded across Eurasia, marked by the construction of burial mounds, or "kurgans," like this one located on the Mongolian steppe. (Credit: William Taylor)

Conclusion: Rewriting the History of Horse Domestication

The study underscores the complexity of using skeletal evidence to determine ancient human activities like horseback riding. While skeletal changes can offer some insights, they are far from definitive proof of horse domestication. To better understand the origins of horseback riding, researchers must rely on a combination of genetics, archaeology, and the study of horse remains.

In the context of the Kurgan hypothesis, the research suggests that the domestication of horses may not have occurred as early as previously believed. As scientists continue to explore this pivotal moment in human history, the study of human and horse remains will remain central to unraveling the full story.

1. Hosek, L., James, R. J., & Taylor, W. T. T. (2024). Tracing horseback riding and transport in the human skeleton. Science Advances, 10(38). https://doi.org/10.1126/sciadv.ado9774