A fresh, comprehensive investigation into human skeletal remains raises questions about a well-established theory in archaeology called the Kurgan hypothesis. This hypothesis posits that humans began domesticating horses as early as the fourth millennium B.C.
Anyone who has spent time riding knows that it can take a toll on the body. But does horseback riding actually alter the structure of a person’s skeleton?
The answer, according to researchers from the University of Colorado Boulder, is quite complex. Their recent study utilized an extensive array of evidence, ranging from medical research on modern riders to historical records of skeletal remains spanning thousands of years.
The findings indicate that horseback ridingcan indeed leave a mark on human skeletons, such as a subtle change in the shape of the hip joint. However, such alterations can’t definitively indicate whether an individual has rode horses throughout their life. Various other activities, including prolonged sitting, can also influence bone structure.
“In archaeology, there are very few cases where we can link a specific activity to changes in the skeleton unequivocally,” stated Lauren Hosek, the study’s lead author and an assistant professor in CU Boulder’s Department of Anthropology.
She and her team shared their results on September 20 in the journal Science Advances.
The implications of this study could affect how researchers view the timeline for when humans first began domesticating horses, and it also brings skepticism to the long-standing Kurgan hypothesis.
The first equestrians
This research is at the heart of a longstanding debate in archaeology, as noted by William Taylor, a co-author of the study and curator of archaeology at the CU Museum of Natural History.
He explained that the earliest indisputable evidence of horses being used for transport comes from the area around the Ural Mountains in Russia, where scientists have discovered horse remains, bridles, and chariots dating back approximately 4,000 years.
Conversely, the Kurgan hypothesis, which originated in the early 20th century, contends that humans and horses formed a close relationship much earlier. Its supporters argue that around the fourth millennium B.C., the Yamnaya people, residing near the Black Sea, first started riding horses across Eurasia. Allegedly, this led to the spread of primitive versions of languages that eventually developed into modern languages, including English and French.
“Much of our understanding of ancient and modern societies relies on knowing when humans began using horses for transportation,” Taylor remarked. “For decades, it has been believed that the distribution of Indo-European languages is somehow linked to horse domestication.”
Recently, some scientists pointed to skeletal remains from the Yamnaya culture dating back to roughly 3500 B.C. as critical evidence supporting the Kurgan hypothesis. They argued that these ancient individuals exhibited wear on their bones likely from horseback riding.
Hips can mislead
However, in their new research, Hosek and Taylor suggest that the situation is not as straightforward.
Hosek has dedicated significant time to studying human bones to uncover historical insights. She explained that bones are not static; they can change shape throughout a person’s life. For instance, a muscle strain can lead to observable changes at the site where the muscle connects to the bone. Consequently, bones may become more porous, or raised areas can develop.
Identifying these clues is not straightforward. The hip joint provides one such example.
Hosek noted that prolonged flexing of the legs at the hip, such as during lengthy horseback rides, can result in friction between the ball and socket of the hip joint. Over time, this friction can transform the round cavity of the hip bone into a more elongated or oval shape. However, she added that this elongation can also occur due to other activities.
Archaeological evidence indicates that before horses were domesticated, ancient humans utilized cattle, donkeys, and wild asses for transport in various parts of western Asia. These early people likely harnessed these animals to pull carts or smaller, two-wheeled vehicles resembling chariots.
“Over time, this repetitive pressure caused by being in a flexed position could induce skeletal changes,” Hosek explained.
She has observed comparable changes in the skeletons of 20th-century Catholic nuns, who didn’t ride horses but frequently took long carriage rides across the American West.
Ultimately, Hosek and Taylor conclude that human remains alone cannot accurately determine when people began riding horses, at least with the current scientific tools available.
“Alone, human skeletons will not provide sufficient evidence,” Hosek stated. “We need to combine that data with insights from genetics, archaeology, and the study of horse remains as well.”
Taylor concluded that the evidence doesn’t seem favorable for the Kurgan hypothesis:
“As of now, there are no indications that the Yamnaya people possessed domestic horses.”
