The history of horse domestication is fascinating. Its importance to mankind is undeniable, bringing with it social and economic upheaval.
Horse domestication advanced communications, transport, food production and warfare. Indeed, wars were won and lost on the back of horses.
The increased mobility of armies and civilians repeatedly changed the course of history, as empires were built and lost.
But the evidence left for us to interpret is not without its challenges.
Some cultures, such as the Romans, left us a wealth of evidence. There are pictures and sculptures of horses being ridden or pulling chariots, as well as writings. Even some of the tack of the day survives, from metal horseshoes to the preserved remains of ancient chariots that once saw action in the hippodrome.
But when we journey back further, to the dawn of horse domestication, the picture becomes far less clear.
The evidence is scant at best and, as as we see below, open to different interpretation.
So, when did horse domestication first occur?
The issue made international headlines in 2009, when the findings of a high-profile study pushed back the earliest known evidence of horse domestication to Khazakhstan around 3500 BC.
The original study, published in the journal Science in 2009, outlined what it described as three independent lines of evidence pointing to horse domestication by the Botai culture some 5500 years ago.
Their findings pushed back evidence of horse domestication about 1000 years further than first thought, and 2000 years earlier than the earliest evidence of domestic horses in Europe.
The findings of University of Exeter researcher Alan Outram and his colleagues were firstly based on analysis of horse leg bones showing that Botai horses resembled Bronze Age domestic horses rather than Paleolithic wild horses from the same region. This suggested that people were selecting wild horses for their physical attributes, which were then exaggerated through breeding.
The British-led international study team also offered evidence that some Botai horses were bridled, perhaps ridden, and ran organic-residue tests which they said pointed to the processing of mare’s milk and carcass products in ceramic containers.
It was clever science.
Their work involved a new technique to search for bit damage caused by horses being harnessed or bridled. And, using a novel method of lipid residue analysis, the researchers also analysed Botai pottery and found traces of fats from horse milk.
Mare’s milk is still drunk in Kazakhstan, a country in which horse traditions run deep, and is usually fermented into a slightly alcoholic drink called koumiss. While it was known that koumiss has been made for centuries, this study showed the practice dates back to the very earliest horse herders.
Thus, they argued, in the fourth millennium BC, horses in Kazakhstan were not just being used for riding, but for food, including milk.
The steppe zones, east of the Ural Mountains in Northern Kazakhstan, are known to have been a prime habitat for wild horses thousands of years ago. They were a commonly hunted animal.
This, they argued, may have set the stage for horse domestication by providing indigenous cultures with access to plentiful wild herds and the opportunity to gain an intimate knowledge of equine behaviour.
Horses appear to have been domesticated in preference to adopting a herding economy based upon domestic cattle, sheep and goats.
However, Russian researchers Pavel Kosintsev and Pavel Kuznetsov were not convinced by their findings.
They laid out the reasons for their doubts in a comment piece in the journal Tyragetia, published by the National Museum of History of Moldova.
The pair, writing in 2013, acknowledged that the study of animal domestication was complicated, and can require the use of many methods from different disciplines.
They noted that one of the reasons for the research team’s conclusion was based on the proportions of metacarpal bones discovered there in 2005-2006.
The Russian pair discussed other horse-bone evidence from the Botai culture, as well as work done at contemporary sites located in Kazakhstan. They argued that the horse bones found during earlier Botai excavations in 1980-1992 belonged to wild horses.
“In our opinion, the inconsistency between the data for 1980-1992 and 2005-2006 excavations at the same Botai settlement should be explained by technical error made during the analysis of the latter, and there is no evidence that horses at Botai were harnessed.”
They also took issue with the evidence cited by the international team of bitting damage on teeth.
When iron bits are used for horses, well-marked bitting damage can be seen. “However, this methodology will not work if bits were made of other materials, softer than metal, such as leather or hair,” they said.
“Until now, only one small copper sheet was found on the Botai settlement.
“There is also no evidence of metal-working at the settlement, and metal bits for horses were not in use at that time.
“The first cheek-pieces appeared at the beginning of the 2nd millennium BCE, and bone or antler mouthpieces had been used for their making. Before this period, bridles were made of leather or hair.”
If domestic horses had been used by the Botai people, their bits would have been made of organic materials that would not have left well-marked traces on teeth or bones.
The presence of any marks on teeth found at the Botai site were likely from some cause other than bitting, they argued. “It is possible that these are the results of an abnormal bite or some mechanical damage.”
Turning to the work on fatty acids on cooking vessels found at Botai, they were sceptical that the archaeological residues could be specifically interpreted as equine milk fat as opposed to other equine fatty tissue.
They argued that none of the findings from the three lines of research could be used as evidence for the existence of domestic horses in Kazakhstan during the Eneolitic/Bronze Age period.
“The culture of the Botai was traditional, with deep roots in the local hunters’ culture of the Late Stone Age,” they wrote. “There are no other known domestic animals at the Botai settlement except dogs.
“All animal bones found at other settlements of this culture belong only to wild breeds. Thus, we suppose that the archaeological culture of Botai was left by humans who were hunting wild horses.
“Simultaneously, in the West, in the Eastern European steppes, the population of the Early Bronze Age possessed herds consisting of hoofed animals.
“It was only at the turn of the 3rd-2nd millennium BCE when the evolution of the Western model of cattle-breeding, and its spread to the East led to the appearance there of chariots pulled by horses known from the finds in the Ural tombs.”
The views of Kosintsev, who is with the Institute of Plant and Animal Ecology in the Ural branch of the Russian Academy of Sciences, and Kuznetsov, who is with the Archaeological Museum of the Volga-region in Samara, highlight not only the challenges in interpreting evidence, but the importance of context.
However, there has also been the discovery at Botai sites of a corral and mats of horse-dung, so the argument is far from over. Investigations are certain to continue.
Debate is healthy, and it is likely interpretations from this window of domestication will continue for years to come.
Timing is just one of the unanswered questions around horse domestication. One theory suggests that there were multiple horse domestication events. In other words, different cultures independently domesticated the horse at different times, rather than one culture “discovering” the value of horses, and the concept spreading rapidly.
There is some fascinating work on the artifacts found at al-Magar, in Saudi Arabia. These discoveries, too, may be providing a window into the earliest years of horse domestication.
Researchers may apply cutting-edge scientific techniques to learn more about ancient artifacts to inform their decision-making. However, at the end of the day it still a matter of expert interpretation. Is the animal a horse? Do those lines or etched marks represent a bridle, cinch, or riding blanket? Does that crude rock drawing show a rider or something else?
The science is challenging and interpretations might not always be universally accepted, but that doesn’t make it any less fascinating.