When did humans start riding horses?

Archaeological research shows that humans first started riding horses about 4,200 years ago, discounting one of the major theories about migration of people across Eurasia.

Horse power was a critical development in human society as it significantly sped up ancient people’s ability to communicate and trade. Riding on horse back remained the fastest means of transportation until the mechanical engine was invented in the 20th century.

All domestic horses today can trace their origins back to the western Russian steppes to the 3rd millennium BCE. But the timeline of horse domestication has remained a topic of debate until now.

This timeline is clarified in a new study published in Nature.

Gathering horse remains across Eurasia, an international research team sequenced the DNA of the horses to track how the animals’ genomes changed over time.

“I have started working on horses about a decade ago. At that time, we only had a handful of ancient genomes,” says first author Pablo Librado from the Institute of Evolutionary Biology (IBE) of Barcelona. “With this new work, we now have several hundreds.”

In particular, the team was able to gain new insight into ancient horses in Central Europe, and the Carpathian and Transylvanian basins.

This area, Librado says, is “central to ongoing debates about horseback riding driving the massive migrations from the steppes around 5,000 years ago, and possibly earlier.”

Three main questions were examined by the researchers using their genetic data:

• When did modern domestic horses begin to spread beyond the area where they were first domesticated?
• When did large-scale breeding of domesticated horses begin?
• When did humans start to influence the natural reproduction cycles of the animals?

Putting these 3 lines of questioning together, the team realised that the turning point was about 4,200 years ago and not earlier.

It was only 4,200 years ago that the genetic data shows horses were sufficiently bred in large enough numbers to sustain growing demand across Eurasia.

The discovery all but discounts the theory that horseback riding was the primary reason for the success of migrations of people coming from the steppes into Europe – often considered the speakers of the proto-Indo-European language.

“One question that puzzled me for years pertains to the scale of the production: how could such a substantial number of horses be bred so suddenly from a relatively small domestication area to meet the increasingly global demand by the turn of the second millennium BCE?” asks coordinator of the research Ludovic Orlando, from the Paul Sabatier University in France.

“Now we have an answer. Breeders controlled the reproduction of the animal so well that they almost halved the time interval between two generations. Put simply, they were able to accelerate the breeding process, effectively doubling their production rate.”

“Our evidence supports two domestications in horses. The first, occurring around 5,500 years ago, aimed to address the decline in horse populations and provide sustenance for populations inhabiting the steppes of Central Asia. The domestic horse as we know it emerged around 4,200 years ago from the second domestication. This one truly transformed human history by providing fast mobility for the first time,” Orlando explains.