Dogs are man's best friend and a new study involving the use of sophisticated 3D imaging reveals just when this relationship likely began.
Findings of the study published in the Nature Scientific Reports have provided evidence that dogs were not domesticated about 30,000 years ago during the late Paleolithic era, when humans were hunter-gatherers as previously suggested, but this occurred only about 15,000 years ago during which the animals evolved from wolves.
For the new study published in the Scientific Reports on Feb. 5, Abby Grace Drake from the Department of Biology of the Skidmore College and colleagues used a 3D method to analyze two canid fossil skulls, one of which was over 30,000 years old. The remains were used as basis for dating dog domestication during the late Paleolithic era.
The researchers found that these fossils, which were once presumed to be dogs, were actually wolves, when they compared the form of the skulls to those of modern and ancient wolves and dogs from Europe and North America.
The technology the researchers used in the study had previously been used for studying human fossils but not to recognize members of the canid family. It, however, allowed the researchers to identify subtle differences between wolves and dogs.
"The difference between a wolf and a dog is largely about the angle of the orbits: in dogs the eyes are oriented forward, and a pronounced angle, called the stop, exists between the forehead and the muzzle. We could tell that the Paleolithic fossils do not have this feature and are clearly wolves," said study author Michael Coquerelle, from the Department of Paleobiology in Spain's Museo Nacional de Ciencias Naturales.
As to why dogs underwent domestication during the Neolithic era when humans first established their permanent settlements and began farming, the researchers said that the permanent settlements during this period would have produced an environment, where sustained selection for tameness could exist for a long time, setting the stage for the domestication of dogs.
"We employ 3D geometric morphometric analyses to compare the cranial morphology of Goyet and Eliseevichi MAE to that of ancient and modern dogs and wolves. We demonstrate that these Paleolithic canids are definitively wolves and not dogs," Drake and colleagues wrote in their study. "Morphologically, these early fossil canids resemble wolves, and thus no longer support the establishment of dog domestication in the Paleolithic."