Two recent studies analyzed the skull shape and genomes of ancient dogs and determined that traveling with and breeding canine companions has been important to humans for over 10,000 years.
Einar Storsul/UnsplashA modern Siberian husky, which has ancestral connections to ancient dogs.
Two new studies published in Science are revealing more information about the history of domestic dogs.
One study analyzed dozens of ancient dog genomes and found that canines were migrating across Eurasia with early humans as far back as 10,000 years ago, showcasing how important the creatures were to our ancestors even during the Stone Age. The second study took a look at hundreds of dog and wolf skulls to determine when exactly the wide range of diversity seen in modern dogs emerged.
This latest research is changing much of what we know about some of the earliest relationships between humans and their canine companions.
A Variety Of Dog Skull Shapes Among Early Human Populations
Allowen Evin, a bioarchaeologist at CNRS University of Montpellier in France, spoke with Nature about the results of the dog skull study. “We often assume that dog diversity emerged since the Victorian period over the last two centuries,” said Evin. “But no — what we found is that from the beginning, there is a huge diversity, much more than what we expected.”
Evin’s research took a look at 3D scans of the skulls of 643 dogs and wolves that lived over the past 50,000 years. The team identified a distinctive dog skull shape — with a shorter snout and wider face than wolves — that first appeared in fossils from northwest Russia that date back nearly 11,000 years.
Around that same time period, dogs associated with late hunter-gatherers and early farming populations showed an “explosion” in skull shapes and sizes, accounting for more than half of the diversity in today’s breeds.
Carly Ameen/University of ExeterTwo of the dog skulls used in the analysis.
“By about 10,000 years ago, half of the amount of diversity present in modern dogs is already present in the Neolithic,” Carly Ameen, a bioarchaeologist at the University of Exeter who co-authored the study, told NPR. “So very early on in our relationship with dogs, we not only change them from wolves, but they begin to change among themselves and generate a lot of diversity.”
This early diversity likely reflects deliberate breeding efforts as humans adapted dogs for specific purposes, including hunting, protection, and companionship, the researchers said. This desire to breed certain traits into canines was evidenced in the second study, too — this time through DNA.
Genome Study Reveals Regionally Distinct Dog Populations
A companion study analyzed 73 ancient dog genomes from East Asia and Central Eurasia, including 17 that were newly sequenced. All of the canines studied lived within the last 10,000 years.
This research revealed that early humans brought their dogs along with them as they migrated across Eurasia. The genome analysis found that different human ancestries tended to be associated with regionally distinct dog populations. For example, ancestry from ancient people in northeastern Siberia was linked to Arctic dogs, whose descendants include modern huskies and sled dogs.
In some cases, however, disconnects between human and dog ancestries in certain populations suggest that canines were traded between civilizations, likely to bring out specific traits in working animals. Laurent Frantz, a population geneticist at Ludwig Maximilians University in Munich who co-led the genome study, noted that dogs with Arctic ancestry proved especially popular, appearing with hunter-gatherers on the Eurasian Steppe and later with Bronze Age populations in southern China.
However, the researchers also noticed that even the earliest samples of known dogs from 11,000 years ago didn’t look much like wolves, which could only mean one thing: Humans already had dogs by that point. Canine domestication, then, had to have happened much earlier.
Sumit Surai/Wikimedia CommonsDogs have been a key part of humans’ lives since ancient times, as evidenced by this mosaic found at Pompeii.
“[B]y 11,000 years, you already had dogs all the way in Siberia and in Europe for thousands of years, probably… long enough for them to become different,” said Frantz. “So we’re looking at a time where everybody had dogs already.”
Despite these new insights, major questions about modern dogs are still unanswered, including exactly when, where, and why wolves were first domesticated.
Remaining Questions About Early Dog Domestication
One major challenge in the research is identifying very early dog fossils, which likely closely resembled those of wolves. Genome studies suggest the main dog lineages began diverging around 20,000 years ago during the Pleistocene period, but confirmed dog fossils from that era remain elusive. None of the 17 Pleistocene skulls analyzed in the new research, for example, showed signs of domestication.
Meanwhile, early dog trade might stretch even further back than the new studies indicate. To find remains from the first domestic dogs, researchers may need to look beyond skulls to other features like lower jaws or rely on DNA analysis of fragmentary remains, scientists said.
“Very early dog has to look very similar to a wolf,” noted Evin.
While answers to these questions may remain elusive for now, one thing is certainly clear: Domesticating wolves and other animals was vital to humanity’s success as a species.
“Without them, we have no food,” Ameen said. “Without them, we have no plants to eat. We have no cereal… It’s possibly one of the most important things that humans have ever done. And the dog is the first species we make this relationship with.”
After reading up on these new studies into domestic dogs’ origins, learn the heartwarming stories of these famous dogs throughout history. Then, check out 44 ancient artifacts that reveal how our ancestors truly lived.
