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Ancient Bovine Jawbone Provides Clues to Domestication

by
Scope Correspondent

Scientific detectives recently described a 10,660-year-old bovine jawbone found in China that could reshape the way we think about the history of human civilization.

Cattle strongly influenced the development of human societies:  Great effort and organization were needed to breed and manage cows, so cattle-farming societies usually became wildly successful at colonizing new regions, according to Johannes Lenstra of Utrecht University.  “Domestication of cattle is not just an interesting event,” said Lenstra, who was not part of the team that studied the jawbone.  “I would like to compare it to the invention of the steam engine, or book printing, or the iPhone.”

The jawbone suggests that the cow it came from could have been gnawing on human-built restraints in northeastern China at about the same time that cattle were first domesticated in present-day Iraq.  The complete lower jaw provides three separate pieces of evidence, which together hint at an early and unsuccessful attempt at domestication, something “completely new, completely unknown, and for most people rather unexpected,” said the study’s lead author, Michael Hofreiter, from the Universities of York and Potsdam.

First, the age of the jaw was determined by radiocarbon dating.  Next, the scientists extracted and analyzed mitochondrial DNA from the bone, which revealed that the jaw’s owner was not closely related either to other ancient cattle or to modern Chinese cows. Finally, archaeologists interpreted a pattern of wear on the teeth as evidence of a stress behavior called “bar-biting.” Animals kept in pens by humans munch on the fences keeping them in, grinding down the teeth on both sides of the mouth, which means that bar-biting is only recognizable when the archaeologists are lucky enough to find a rare intact jaw. “It’s a weird combination of characteristics that nobody would expect,” said Greger Larson, a professor at Durham University not affiliated with the study.

Richard Meadow of Harvard University, who was also not part of the study, is not convinced by the interpretation of the wear pattern on the teeth and thinks more information is required to claim that the jaw suggests the beginnings of domestication.  For example, an upper jaw could corroborate the diagnosis of bar-biting, or the chemical composition of the surface of the teeth could determine if the cattle ate anything unusual that would indicate human intervention. Even so, the research “has a potential for causing us to look again at concepts of domestication, animal keeping, and its role in society,” Meadow said.

Paolo Ajmone Marsan agrees:  “Investigating the history of cattle gives us information on human history,” said Ajmone Marsan, of the Università Cattolica del Sacro Cuore, Piacenza, who was not connected with this research.  “Taken together with other papers that came out in the last few years, this discovery is changing the picture of domestication.”

If the Chinese jawbone is indeed evidence of an attempt at domestication, Lenstra finds it intriguing that, in contrast to cattle domestication in other places, this effort was unsuccessful, since there is no other known evidence of domesticated cattle in that region of China for another 6,000 years.

The apparent failure of human management to turn this cattle specimen into a tame breed of ancient Chinese cows is consistent with an emerging picture of domestication as a complicated process.  Ajmone Marsan mentioned as an example a recent study that indicated that humans expanded the wild goat population before, not after, the goats were successfully tamed, contrasting with the conventional view that the population only grows after domestication.

“I personally think we have to rethink domestication,” Hofreiter said.  “It’s a process with dead ends and multiple attempts, and a lot more trial and error than people thought.”

Our understanding of our own history through our relationship with animals will most likely continue to evolve in the coming years due to technological advances in analyzing ancient DNA combined with more established techniques like carbon dating and classical archeological methods.  “I’m expecting that the next few years will further clarify what has happened in the past,” said Ajmone Marsan

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