Woolly mammoths may have gone extinct, in part, because of dogs, reports a new study.
Mammoth megasites, like one near the Arctic Circle in Siberia, are vast collections of thousands of bones, mostly those of ancient woolly mammoths. There are around 30 such areas around the world known to biologists. Some of the regions contain remains of tens of thousands of animals, and even huts made of mammoth bones, arranged in complex patterns.
Pat Shipman, an anthropologist at Pennsylvania State University, has been studying these sites since 2009. She believes they may have been created by human hunters, aided by some of the first dogs in the world.
"One of the greatest puzzles about these sites is how such large numbers of mammoths could have been killed with the weapons available during that time," Shipman said.
Between 45,000 and 15,000 years ago, humans began killing mammoths at a much faster rate than ever before.
Some earlier research suggested mammoths in these mass graves died of natural causes, and early human hunters. Shipman showed errors in these early studies, and suggested a new weapon helped early humans hunt the beasts.
Some bones, believed to be those of wolves, were discovered to be those of domesticated dogs. Mietje Germonpré of the Royal Belgian Institute of Natural Sciences made this finding, which provided Shipman with the inspiration that canines may have provided humans with the tool they needed to hunt the animals in far greater numbers.
"Dogs help hunters find prey faster and more often, and dogs also can surround a large animal and hold it in place by growling and charging while hunters move in. Both of these effects would increase hunting success," Shipman stated in a university press release.
Canines could have also assisted early hunters bringing prey home. Extra protein provided by more frequent kills could have made humans stronger and more prolific.
Hervé Bocherens and Dorothée Drucker of the University of Tubingen in Germany analyzed remains of dogs and wolves recovered from mammoth megasites. They discovered dogs ate a different diet than wolves, suggesting they may have been fed by humans. Study of mitochondrial DNA from the specimens reveals the dogs seen at the site possessed several genetic differences from wolves. This could suggest the dogs found at the sites were not ancestors of modern pets, but a unique species of wolf that is now extinct.
Shipman believes her theory could be supported by further evidence of domesticated dogs yet to be discovered at other mammoth megasites.