Researchers have uncovered a 33,000-year-old dog skull in the Altai Mountain region of Siberia in a cave called Razboinichya.
This find is noteworthy for its historic value, however scientists also say it suggests modern dogs might be descended from multiple ancestors.
This prehistoric skull is the oldest known evidence of dog domestication. According to a Jan. 23 press release issued from the University of Arizona, this fossil, along with remains from an "equally ancient dog" found in a Belgian cave, jointly suggest that multiple geographic regions were domesticating dogs around the same time-frame.
"In other words, man's best friends may have originated from more than one ancient ancestor, contrary to what some DNA evidence previously has indicated," the press release said.
"Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics," said Greg Hodgins, a co-author of the study. "Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth."
The ancient dog skull is said to be well-preserved and researchers were able to closely examine the skull, teeth and mandibles and take numerous measurements of the remains.
Credit: Nikolai D. Ovodov
The 33,000-year-old skull of a domesticated dog was extraordinarily well preserved in the Razboinichya cave in the Altai Mountains of Siberia.
"The argument that it is domesticated is pretty solid," said Hodgins, a researcher at the University of Arizona's Accelerator Mass Spectrometry Laboratory. "What's interesting is that it doesn't appear to be an ancestor of modern dogs."
Using radiocarbon dating, or carbon-14, the laboratory at the University of Arizona was able to determine the age of the skull found in the Siberian cave.
Scientists say the remains of the 33,000-year-old dog predate the Last Glacial Maximum (LGM) which occurred somewhere between about 26,000 and 19,000 years ago. After the disruption to life the ice sheets caused, both the Siberian and Belgian dogs do not appear to have survived the LGM, researchers say.
However the dog remains left behind indicate throughout the history of humans that domestication of dogs has occurred throughout time and in different geographical spaces, meaning modern dogs may not have all descended from the same place with a single common ancestor.
"In terms of human history, before the last glacial maximum people were living with wolves or canid species in widely separated geographical areas of Euro-Asia, and had been living with them long enough that they were actually changing evolutionarily," said Hodgins. "And then climate change happened, human habitation patterns changed and those relationships with those particular lineages of animals apparently didn't survive."
The study pointed out the scarcity of pre-LGM dog-like animals and incomplete remains has been an obstacle to understanding the "morphological features of transitional forms between wild wolves and domesticated dogs in temporal perspective." The recent fossil finding is described to be in "extraordinary" condition and scientists believe it to be unlike ancient and modern wolves. All of which has led researchers, upon examination, to believe dogs may not have a single place of origin.
Essentially, researchers believe they may have evidence that dogs were man's best friend far longer than previously thought. Dogs, even today, have different relationships with humans than other animals bred for food and agriculture used for human consumption, such as cows, chickens, goats and sheep.
Hodgins said "Those are different relationships than humans may have with dogs. The dogs are not necessarily providing products or meat. They are probably providing protection, companionship and perhaps helping on the hunt. And it's really interesting that this appears to have happened first out of all human relationships with animals."
University of Arizona physicist Greg Hodgins awaits results from the accelerator mass spectrometer.