Although mammoths had been hunted by humans and their relatives and ancestors for at least a million years, sites yielding stone tools and extraordinary numbers of dead mammoths - some containing the remains of hundreds of individuals - suddenly became common in central and eastern Eurasia between about 45,000 and 15,000 years ago. Some have huts built of mammoth bones in complex, geometric patterns, as well as heaps of butchered mammoth bones.
     Recent work by a team led by Mietje Germonpré, of the Royal Belgian Institute of Natural Sciences, uncovered evidence that some large carnivores at these sites were early domesticated dogs, not wolves.
     According to Penn State Professor Emerita Pat Shipman, "Dogs help hunters find prey faster and more often, and can surround a large animal... while hunters move in. Furthermore, large dogs like those identified by Germonpré either can help carry the prey home or, by guarding the carcass from other carnivores, can make it possible for the hunters to camp at the kill sites."
     Another unusual feature of these sites is the presence of extraordinary numbers of other predators, particularly wolves and foxes. "If humans were working and living with domesticated dogs or even semi-domesticated wolves at these archaeological sites, we would expect to find the new focus on killing the wild wolves that we see there."
     Two other types of studies have yielded data that support Shipman's hypothesis. Hervé Bocherens and Dorothée Drucker, of the University of Tubingen in Germany, found that the individuals identified as dogs had different diets from those identified as wolves, possibly indicating feeding by humans. Analysis of mitochondrial DNA by Olaf Thalmann of the University of Turku in Finland, and others, show the dogs have a distinctive genetic signature that is not known from any other canid.
     "Since mitochondrial DNA is carried only by females, this finding may indicate that these odd canids did not give rise to modern domesticated dogs and were simply a peculiar, extinct group of wolves," Shipman says. "Alternatively, it may indicate that early humans did domesticate wolves into dogs or a doglike group, but the female canids interbred with wild wolf males and so the distinctive female mitochondrial DNA lineage was lost."