Domestication difficult | With few wild aurochs in captivity, the progenitors of founder herds were few
LINDELL BEACH, B.C. — Modern science has told us taurine cattle descended from wild aurochs about 10,500 years ago.
But it took the combined analysis of archaeozoological and genetic data using mitochondrial DNA from 15 Neolithic to Iron Age Iranian domestic cattle fossils to estimate that only 80 female aurochs were initially domesticated to form the founder herd.
This information fits with archaeological data suggesting that domestication was not widespread, but took place in a restricted area, most likely because of the difficulty of containing, managing and breeding dangerous wild oxen.
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According to the research paper, modern Taurine cattle descended from a small number of near-eastern founders. It took almost 2,000 years from the earliest years of taming wild aurochs to clear evidence of their domestication.
The low number of 80 founder females indicates a restricted number of initial captures and calculates to less than two animals per generation, which is extremely low.
Aurochs were common throughout Europe and Asia so there would have been many opportunities to capture and contain them.
Centuries of managing just a few wild animals could feasibly have been done by a small community such as a couple of Neolithic villages.
Two sites in particular fit that profile. Dja’de and Cayonu are rich in human and animal artefacts and they reveal the earliest signs of wild auroch domestication.
Geographically, these two sites were close enough — less than 250 kilometres apart — to allow an exchange of skills and husbandry techniques at a time when people were shifting from being nomadic to settling down and committing to animal husbandry.
“The best way to describe a wild auroch is like a moody, angry lorry (truck),” said Mark Thomas, geneticist at the UCL Research Department of Genetics, Evolution and Environment and an author of the study.
“There were a whole series of processes going on here (with the do-mestication of) goats and the cultivation of crops. When it came to cattle, it required some conditions, like being sedentary. It’s very difficult to imagine people domesticating wild aurochs while they were mobile. There weren’t the technologies in place and they would have had to start breeding them for docile characteristics very quickly.”
Managing the wild cattle would have been difficult if the people had not stayed in one location.
Handling large, aggressive males was likely overwhelming, resulting in limited successful cattle domestication and few progenitors for founder herds.
Some method of containment to control those early animals had to have been developed to some extent because, as Thomas pointed out, aurochs turned up in Cyprus during the early stages of domestication. He hypothesized those animals must have been taken by boat, likely as calves.
Containment and early handling of calves would have made them more amenable to being worked as there is evidence of their use to carry loads in the early stages of domestication.
“We simulated different scenarios (in a computer) with different numbers of animals that were first domesticated then tried to see which of those different simulations gave us the best data that looked like the real data today. It turned out that the ones that were the best had a small number of animals initially domesticated. We modelled it as a single event,” Thomas said.
He said researchers were looking at mtDNA, the female line from early cattle.
The problem with looking at modern mtDNA is that the genetics fall into different lineages and do not show how the animals first became domesticated, or how many.
“So what we really needed to do was get DNA from very early cattle.”
He said if there had been more than one domestication event and each event had fed its genetics into today’s modern cattle stock, then greater genetic variation would have been preserved by chance.
The effect of that is that fewer animals would have been needed for domestication in the first place to get the genetic pattern that exists in cattle today. He said those first cattle couldn’t have added up to more than 80 animals.
One of the challenges of the study was extracting reliable DNA that hadn’t been contaminated.
“If the (samples) were in Lapland (where it’s cold) they would be fine,” said Thomas. “But they were domesticated in quite a hot place and the absolutely critical factor when it comes to DNA either breaking down or being preserved in bones over a long time is temperature. These samples aren’t from a cold place. It was a lot of work done by (the team) and they managed to produce some reliable things from some samples.”
While the cattle’s value as animals to haul goods and provide meat was evident early on, their contribution as milk producers is less clear, especially given that the onset of domestication happened during the Early Pre-Pottery Neolithic period 10,800 to 10,300 years ago.
“I don’t think we are able to really say whether an animal was being milked,” said Thomas.
“There are two ways to tell whether an animal was used for dairying. One is to detect dairy fats on pottery. The other one is to look at the age and sex ratios. The idea is that if you are using animals for milk you will slaughter most of the bulls but keep the cows to a decent age. If you are going to use cattle for traction, bulls are stronger than cows so you’ll keep most bulls alive to a decent age. These are the economic activities as to which sexes you slaughter and which you keep. There’s no reason why that approach couldn’t have been applied to those very early animals.”
The results of the study conducted by scientists from the National Centre for Scientific Research and the National Museum of Natural History in France, the University of Mainz in Germany and the University College London in the United Kingdom were published in the journal Molecular Biology and Evolution.
The archaeological digs included sites in the Middle Euphrates Valley and the High Tigris Valley in today’s southeastern Turkey and northeastern Syria, as well as the northwestern corner of Iran.
Along with northern Iraq, the region forms an arc that is part of the ancient Fertile Crescent, the cradle of farming.
