understanding of the ways in which dogs are different from wolves, we are also learning more about how we, as humans, have helped to make the dog different. The domestication of dogs has been revealed as a complex process, more convoluted than that of any other animal, leading not only to radical changes in the shape and size of their physical bodies but also to an almost complete reorganization of their behavior. Furthermore, while humans have guided that process, it is only in the past century and a half, and only in the West, that we have taken control of it completely. For ten thousand years or more, as the purposes for which dogs were valued changed and proliferated, dogs have coexisted and coevolved with us. Essentially, they domesticated themselves as much as we domesticated them.
When was the dog domesticated? Until fifteen years ago, the answer was thought to be simple. The oldest remains of dogs found by archaeologists were carbon-dated to be no more than twelve thousand years old, fourteen thousand at most. This timeline placed the first dogs before the beginnings of agriculture about ten thousand years ago, and well before the domestication of any other animal. So the dog was, for this reason alone, considered a special case: the pioneer for all subsequent domestications, such as goats, sheep, cattle, and pigs. Because it was domesticated so early in the history of humans, there is little detailed evidence as to how wolves became dogsâa paucity of information that has left a great deal of room for speculation as to why and where this first occurred. Until fifteen years ago, however, at least the âwhenâ seemed well established: No bones had been found that both unequivocally belongedto a dog and were more than fourteen thousand years old, so domestication must have occurred no earlier than about fifteen thousand years ago.
Then, in 1997, a team of scientists from the United States and Sweden made an astonishing claim: They had sequenced DNA from living dogs and wolves, and the findings indicated that domestication could have taken place more than a hundred thousand years earlier. 1 If this was true, it would mean that dogs were manâs companions not just at the birth of agriculture but right at the dawn of our own speciesâas soon as modern humans had emerged from Africa, where they had evolved, and encountered grey wolves (which do not occur in Africa) for the first time. This announcement triggered a minor epidemic of speculation about the possible coevolution of man and dog. Most archaeologists rejected the idea, pointing to the complete lack of dog remains that could be dated any earlier than fourteen thousand years ago. But there was nothing intrinsically wrong with the DNA data, even though its interpretation was still open to debate. Dogs, it seemed, joined us during our pre-agricultural origins.
Since 1997, there has been a steady flow of more detailed studies of dog and wolf DNA, and, as a result of these, our conclusions about the exact moment of the dogâs domestication have changed and are still changing today. DNA technology is relatively new, and while it may give unequivocal answers when used for âfingerprintingâ (e.g., confirming the parentage of a particular puppy in a dispute over pedigrees), its use in reconstructing events long since passed is much more open to interpretation. Different types of DNA can give different answers; for example, the story told by the type contained in the nucleus of most mammalsâ cells (the subcellular organelle where paternal and maternal DNA mix) is often different from that told by the type associated with other parts of the cell, such as the mitochondria (which contains only maternal DNA). As new analyses have appeared and been integrated into the picture, the estimate that dogs might have been domesticated more than a hundred thousand years ago has since been revised down considerablyâto between fifteen thousand
When was the dog domesticated? Until fifteen years ago, the answer was thought to be simple. The oldest remains of dogs found by archaeologists were carbon-dated to be no more than twelve thousand years old, fourteen thousand at most. This timeline placed the first dogs before the beginnings of agriculture about ten thousand years ago, and well before the domestication of any other animal. So the dog was, for this reason alone, considered a special case: the pioneer for all subsequent domestications, such as goats, sheep, cattle, and pigs. Because it was domesticated so early in the history of humans, there is little detailed evidence as to how wolves became dogsâa paucity of information that has left a great deal of room for speculation as to why and where this first occurred. Until fifteen years ago, however, at least the âwhenâ seemed well established: No bones had been found that both unequivocally belongedto a dog and were more than fourteen thousand years old, so domestication must have occurred no earlier than about fifteen thousand years ago.
Then, in 1997, a team of scientists from the United States and Sweden made an astonishing claim: They had sequenced DNA from living dogs and wolves, and the findings indicated that domestication could have taken place more than a hundred thousand years earlier. 1 If this was true, it would mean that dogs were manâs companions not just at the birth of agriculture but right at the dawn of our own speciesâas soon as modern humans had emerged from Africa, where they had evolved, and encountered grey wolves (which do not occur in Africa) for the first time. This announcement triggered a minor epidemic of speculation about the possible coevolution of man and dog. Most archaeologists rejected the idea, pointing to the complete lack of dog remains that could be dated any earlier than fourteen thousand years ago. But there was nothing intrinsically wrong with the DNA data, even though its interpretation was still open to debate. Dogs, it seemed, joined us during our pre-agricultural origins.
Since 1997, there has been a steady flow of more detailed studies of dog and wolf DNA, and, as a result of these, our conclusions about the exact moment of the dogâs domestication have changed and are still changing today. DNA technology is relatively new, and while it may give unequivocal answers when used for âfingerprintingâ (e.g., confirming the parentage of a particular puppy in a dispute over pedigrees), its use in reconstructing events long since passed is much more open to interpretation. Different types of DNA can give different answers; for example, the story told by the type contained in the nucleus of most mammalsâ cells (the subcellular organelle where paternal and maternal DNA mix) is often different from that told by the type associated with other parts of the cell, such as the mitochondria (which contains only maternal DNA). As new analyses have appeared and been integrated into the picture, the estimate that dogs might have been domesticated more than a hundred thousand years ago has since been revised down considerablyâto between fifteen thousand
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