How horses changed human history 4,200 years ago

Horse herders riding, guiding, catching or enjoying their horses in Inner Mongolia, China, July 2019. Credit: Ludovic Orlando.

All the horses we see today, from racing champions to gentle ponies, trace their origins back to the western Russian steppes about 4,200 years ago.

However, the exact timeline of when horses were first domesticated and used by humans has been a topic of debate among scientists.

A recent study published in Nature sheds light on this topic.

According to the study, the widespread use of domestic horses began around 4,200 years ago.

This period marked a significant shift in human history as horses revolutionized communication and trade across Eurasia, connecting diverse cultures like never before.

The research, led by Ludovic Orlando from the Center of Anthropobiology and Genomics of Toulouse, involved 133 researchers from 113 institutions worldwide.

They collected horse remains from archaeological sites across Eurasia and used radiocarbon dating and ancient DNA sequencing to understand the genetic changes that happened as horse domestication spread.

Pablo Librado, the first author of the study and now a scientist at the Institut de Biologia Evolutiva in Barcelona, mentioned, “A decade ago, we had only a few ancient horse genomes. Now, we have hundreds.” The research focused on Central Europe and the Carpathian and Transylvanian regions, areas central to debates about horseback riding and migrations from the steppes around 5,000 years ago.

The researchers looked for three key indicators of early horse husbandry. First, they tracked when the ancestors of modern horses spread beyond their original homeland. Next, they studied horse population changes during the third millennium BCE to pinpoint the earliest signs of breeding and large-scale horse production. Finally, they found evidence of significant changes in horse reproductive lifespans, indicating early breeders were deliberately controlling horse reproduction.

All these findings pointed to around 4,200 years ago as the time when domestic horses were produced in large numbers to meet the growing demand across the continent. This marked the true beginning of horse-based transportation, which remained the fastest mode of travel until the 20th century when mechanical engines were invented.

Ancient DNA research showed earlier changes in the genetic landscape of Europeans, following migrations from the steppes. However, the genetic map of horses changed much later, suggesting that horseback riding did not drive these early human migrations, even though horse-related terms are common in many Indo-European languages.

Ludovic Orlando noted that early breeders accelerated the horse breeding process by almost halving the time between generations, effectively doubling their production rate to meet the global demand by the turn of the second millennium BCE.

The new methodology developed in this study, which measures generation times using ancient genomes, has great potential. It can be used to study breeding patterns in other domestic species and even understand the generation intervals of our hunter-gatherer ancestors.

Interestingly, the study also found brief generational intervals within a distinct lineage of horses from Botai, Central Asia. These horses were used for milking and harnessing, but unlike other horses, their genetic makeup remained local and did not spread across Eurasia.

The study supports the idea of two separate horse domestication events. The first, around 5,500 years ago, aimed to provide resources like meat and milk for people in Central Asia. The second, around 4,200 years ago, led to the domestic horses we know today and transformed human history by enabling fast mobility.

In conclusion, the rise of horse power around 4,200 years ago was a pivotal moment in human history, connecting cultures and speeding up communication and trade across vast distances.

Source: KSR.