For a long time, archaeologists generally believed that horses were first domesticated during the Bronze Age.
That was when mankind first began using metal regularly for a wide variety of purposes, from household tools to weapons. Archaeological digs at Bronze Age sites have often turned up metal bits, proving that horses were being ridden by that time.
But the excavation of a much earlier site in northern Kazakhstan has now produced evidence that horses may have been tamed and ridden a full 1,000 years earlier. This was when men were still mostly relying upon stone tools and making limited use of copper.
"Conventional wisdom would have it that horses were domesticated in the Bronze Age, sometime around 2,000 B.C., perhaps 2,500 B.C. But what we found in this study is that we have very clear evidence of horses being domesticated as early as 3,500 B.C. in the Botai culture, which is in northern Kazakhstan," says Alan Outram, an archaeologist at Britain's University of Exeter who led the team of scientists excavating what appears to have been a horse farm maintained by the Kazakh people of the ancient Botai culture. "And it is not just that we have found that they have been domesticated for food -- but these animals also appear to have been ridden and also milked."
The team published its findings this past week in the British-American academic journal "Science."
Central Asia has previously been suggested as a place where horses may have been domesticated, in addition to other centers of animal domestication such as the Mideast and China. But the new research adds more detail to the story.
At the site, the archaeologists found the remains of horses' bones and teeth as well as shards of pottery. By examining these closely, they have been able to put together a picture of daily life there.
The horses' bones show the marks left by stone axes and knives used to butcher the animals for meat. That is no surprise, because for centuries before, if not millennia, men had been hunting wild horses.
But what was surprising was to find traces of horses' milk in the remains of the clay jars.
Outram says that because pottery can preserve remnants of what was stored in it, the shards revealed their secrets even after thousands of years.
"Prehistoric pottery, which isn't glazed usually, absorbs a lot of the food that is in it, it soaks into the pottery fabric," Outram says. "The fat that is in food often preserves remarkably well, over thousands of years, because it is trapped in there away from chemical attack or bacterial attack in the soil. And you are able to extract [the fat] and carry out a number of really quite complex analyses on it which indicate what species group it comes from [and] in some cases also what type of foodstuff it was."
The evidence that men were milking horses at the time is perhaps proof enough that horses were already being kept as livestock, much like goats and sheep. But the team also found clear signs that the horses may have been sufficiently tamed to be ridden as well.
"We found evidence that these particular horses had been ridden or at least harnessed," Outram says. He says wear in the horses' mouths of the type they discovered "doesn't occur through natural diet or any other natural process."
"You also get changes to the jaw itself, because as that harness is hitting against the gum in the jaw it irritates the jaw and can cause extra bone growth in that area," Outram says, "and what we had on these Botai horses was both some very clear examples of the bit wear on the teeth [and] also changes to the jaw."
Outram adds that the harnesses of the time were likely leather, so no trace of them remains today. But the scientists did find other tools used for smoothing leather strips into long supple cords of the kind that harnesses would be made of.
New Window On Prehistoric Era
If the horse was indeed domesticated this early, the discovery could change many of our notions of how people moved about in the prehistoric era. Horses not only give their riders the ability to travel and trade over vast distances, but also a distinct advantage in warfare.
The British team worked with Kazakh archaeologists who have long suspected that people domesticated horses much earlier than the Bronze Age. Among the most active of those archaeologists is Viktor Zaibert of the University of Kokshetau in Kazakhstan's northern Akmola region.
Outram says Zaibert and others see a direct connection between the horse culture of the prehistoric sites and Kazakhs' continuing horse culture today.
"Viktor Zaibert has believed for a very long time that [domestication of horses] was going on at the site he was excavating, but the absolute conclusive proof that would convince the world's academics was not there until recently," Outram says. "But this is something that within Kazakh circles they always thought was the case. Within Kazakhstan, they are still very interested in their horse culture -- and it is a very important aspect of their culture, and many traditional Kazakhs still milk horses and drink the drink that comes from it, which is a fermented drink called 'koumiss.'"
It is too early to know if the people of the prehistoric Botai culture enjoyed koumiss just as Central Asians do today. But fermenting mare's milk into that sharply sour, but refreshing, form is necessary for storing it any length of time, so it, too, is likely to have been an early invention.
"I once asked an old Kazakh gentleman [how Kazakhs acquired their taste for koumiss] and he said it is because the fresh milk tastes of nothing -- we only give that to children," Outram says. "And I thought about that and I thought, well, that is probably the case; people have developed a taste for it and in the past, of course, without refrigeration, if you were going to keep the milk for any time then it would have to be in some sort of soured or fermented state."
Just The Start
The British archaeologist says that -- as with so many scientific discoveries -- the new evidence that horses were domesticated earlier than we thought not only answers some questions, it also raises many more.
Those include whether horses might have been domesticated still earlier at other sites in Central Asia that have not yet been investigated.
"I think this is the start of our research to a large degree," Outram says. "I think horses were very important in the whole general region, and having got this site, and having found that this site had really quite a developed package of horse pastoralism at this early date, [then that] might be suggestive that there are yet earlier sites to find. So I think this is the start of our research rather than the end point of it, and I now have to try and apply all these methods to see if we can see how far-spread this was at this date."
The biggest question of all may be how the culture of taming and using horses spread across Eurasia. Did it develop in just one place, or several places independently?
For now, that remains a puzzle for future archaeologists to solve.
The research at the northern Kazakh site was funded by Britain's Natural Environment Research Council, the British Academy, and the U.S. National Science Fund.