America’s first dogs lived with people for thousands of years. Then they vanished
When 19th century naturalists and explorers first encountered the dogs of Native Americans, they were shocked by the canines wolflike appearance. The animals were large and strong, and they didnt bark—they howled. “If I was to meet with one of them in the woods,” remarked John James Audubon, “I should most assuredly kill it.”
But today, these dogs and their kin are nowhere to be found, their genetic legacy wiped from the genomes of all living canines. Now, DNA recovered from several of these ancient animals has revealed where Americas first dogs came from—and how they may have disappeared.
“Its really great research,” says Jennifer Raff, an anthropological geneticist at the University of Kansas in Lawrence and an expert on the peopling of North America. The work supports emerging evidence that the first Americans did not bring dogs with them. Instead, says Raff, the animals may have come thousands of years later.
In the 1960s and 1970s, archaeologists excavated two sites in western Illinois, where ancient hunter-gatherers collected shellfish from a nearby river and stalked deer in surrounding forests. These people also appear to have buried their dogs: One was found at a site known as Stilwell II, and four at a site called Koster, curled up in individual gravelike pits.
Radiocarbon analysis of the bones reveals that they are around 10,000 years old, making these canines the oldest dogs known in the Americas, researchers report on the bioRxiv server. It also makes these the oldest solo dog burials anywhere in the world.
The Stilwell II dog was about the size of an English setter, whereas the Koster dogs were smaller and slenderer, says the studys lead author, Angela Perri, a zooarchaeologist at Durham University in the United Kingdom. “It wouldnt be surprising if they were all used as hunting dogs.” But where did they come from in the first place?
A second study, published today in Science, may have the answer. A large, international team of researchers sequenced DNA from the mitochondria, or cellular power plants, of 71 North American and Siberian dog bones—including from one of the Koster dogs—dated from about 10,000 to 1000 years ago. When they compared this material, which is passed down only by the mother, to that of 145 modern and ancient dogs, they discovered that the ancient American dogs have a genetic signature not found in any other canines.
“They form their own group that has their own story,” says Perri, also a lead author on the Science paper. That means the wolflike dogs Audubon encountered were indeed genetically distinct from European ones.
These “precontact dogs,” as the team calls them, are most closely related to 9000-year-old dogs from Russias Zhokhov Island, hundreds of kilometers north of the Siberian mainland. By assuming a relatively constant DNA mutation rate and using it as a “molecular clock,” the team concludes that the two groups of dogs may have shared an ancestor nearly 16,000 years ago. Its still unclear exactly where or when dogs arose, but it could have been around that time.
Taken together with archaeological findings, the data suggest that the first dogs may have come to the Americas from Siberia thousands of years after the first people, says team leader Laurent Frantz, an evolutionary geneticist at the University of Oxford in the United Kingdom. Humans likely entered the Americas around 16,000 years ago over the Bering land bridge, which connected Siberia to Alaska. The bridge disappeared about 11,000 years ago—by which time dogs must have already made it over, Frantz says.
Dogs may have hung out with people in Alaska for a while, or a few may have traveled with humans to the interior of North America, where they ended up in sites like Koster and Sitwell II. “People were moving around a lot,” Raff says. Once they saw how useful dogs were—for tracking deer, hauling supplies, and guarding camps—humans might have started bringing more of them along for the journey.
“Its a tidy story that adds some grounding for what people thought was happening,” says Melinda Zeder, an archaeozoologist at the Smithsonian Institutions National Museum of Natural History in Washington, D.C. But she notes that molecular clocks are just an approximation and other mysterious bones found in Siberia and the Yukon may belong to dogs, possibly pushing their arrival in the Americas earlier by thousands of years. “Its hard to draw a firm conclusion.”
Additional analysis of the nuclear genome—inherited from both parents—of seven precontact dogs supports the idea that they are genetically distinct. Their closest living relatives are Arctic breeds such as Alaskan malamutes and Siberian huskies. These modern dogs may have come from the same Siberian source population as the precontact dogs, but thousands of years later. “If you have an Arctic dog, you likely have an old dog,” Perri says. “If you have any other dog, it probably came from Europe or Asia a lot more recently.”
That goes even for supposedly ancient dogs like the hairless Mexican Xoloitzcuintli, which is believed to have been around for thousands of years. “Todays dogs may look the same as those dogs,” Frantz says. But according to the samples taken so far, “their genetics are totally different.”
Indeed, the team found almost no genetic trace of precontact dogs in any modern dogs. “By and large, their genetic signature has vanished,” Perri says. Both she and Frantz speculate that, just as European colonists wiped out large numbers of Native Americans with their diseases, the European dogs may have devastated American dogs even more. Europeans also may have feared these wild-looking dogs, as Audubon did, and tried to wipe them out, Perri says.
The only trace of these early dogs may survive in a sexually transmitted canine cancer, which has retained the genetic signature of the first dog it plagued. When the team compared the genomes of two of these tumors to modern and ancient dog genomes, the DNA most closely resembled that of precontact dogs, perhaps one that lived about 8000 years ago. “Its fascinating,” says Frantz, “but at the moment it doesnt tell us much about the history of Americas first dogs.”
If people didnt bring dogs over with them right away, it could be because they didnt know how useful they would be. Or it could simply be that dogs didnt exist yet. When this alliance did form in the Americas, it likely mirrored one taking place all over the world, where dogs were used for hunting, guarding, or simple companionship. “Its insane that we would have started a relationship with an animal that could hurt us and compete with us,” Perri says. “There must have been a good reason.”
*Correction, 5 July, 7 p.m.: This story has been updated to reflect the fact that the first study is only available on bioRxiv. Angela Perris affiliation has also been updated.
*Correction, 1 August, 3:50 p.m.: An earlier version of this story stated that the Xoloitzcuintli came from South America. It is actually from Mexico.
David Grimm is the Online News Editor of Science.
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An analysis of the data revealed that the earliest dogs in North America arrived here already domesticated more than 10,000 years ago. The researchers think they probably came alongside humans who crossed a land bridge between Alaska and Siberia.
The arrival of the first Europeans in the Americas in the 15th century didn’t just affect the lives of native people already living here. It also took a devastating toll on their pets.
Although the study did not reveal what killed off the first group of American dogs, Frantz suggests that their demise was likely due to a mix of disease, cultural persecution and biological changes that started when the first Europeans arrived in the “new” world.
In a paper published Thursday in Science, an international team of archaeologists and geneticists reports that the lineage of dogs that thrived alongside Native Americans for thousands of years was essentially wiped out, thanks to the arrival of canines from Europe.
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North America’s first dogs arrived with humans who crossed a land bridge from Northeast Asia around 10,000 years ago or earlier, an analysis of ancient dogs’ DNA suggests.
Those early American dogs derived from a Siberian ancestor, not North American wolves as some researchers have presumed, an international team reports in the July 6 Science. Genetic traces of ancient American dogs have nearly vanished from present-day pooches, possibly because European colonists selectively bred their own dogs starting around 500 years ago.
Researchers reached that conclusion based on analyses of 71 mitochondrial genomes and seven nuclear genomes of dogs excavated at ancient North American and Siberian sites. Those data were compared with DNA from modern dogs and wolves.
What Happened to the Pre-Contact Dogs?
Dogs have been companions to humans for many millennia, but exactly when this relationship started is highly debated among scientists.
A study published this week in the Proceedings of the National Academy of Sciences reveals that canine domestication may have first occurred in Siberia 23,000 years ago when humans and wolves were isolated together during the Last Glacial Maximum. After this initial domestication event, dogs most likely followed humans when they migrated across the Bering Land Bridge from East Asia to the Americas 15,000 years ago, reports Megan Marples for CNN.
“Wolves likely learned that scavenging from humans regularly was an easy free meal, while humans allowed this to happen so long as wolves were not aggressive or threatening,” Angela Perri, an archaeologist at Durham University and lead author of the study tells CNN.
The study was brought to fruition after Perri and her co-authors—David Meltzer, an archeologist at Southern Methodist University, and Gregor Larson, a scientist from Oxford University—were brainstorming how DNA evidence tells the story of migrating humans and dogs, reports James Gorman for the New York Times. After the authors scribbled down ideas on a whiteboard, they saw that both humans and canines had similar migration patterns and divergence that could explain how dogs and humans began their bond, reports the New York Times.
To see if the similarities between the timelines linked up with archeological evidence, Perri and her team analyzed the genome of 200 ancient dogs from around the world. They found that the canines had one genetic signature, A2b, in common. Once they reached the New World 15,000 years ago, they dispersed into four groups, reports David Grimm for Science.
The researchers found this dispersal matched a similar migration pattern of ancestral Native Americans that descended from Northern Siberia about 21,000 years ago. Connecting these timeline events between humans and dogs, the researchers concluded that humans must have brought dogs into the Americas somewhere around 15,000 years ago.
“Dogs are not going to go to the new world without people,” Meltzer tells the New York Times.
Further exploring the dogs’ genetic evidence, the team found all dogs with the genetic signature A2b descended from the same Siberian canines roughly 23,000 years ago, Science reports.
Looking back at human’s ancestral timeline and genetic evidence, the researchers found that ancient Northern Siberians intermingled with ancestral Native Americans before crossing the land bridge into the Americas. These meetings could have resulted in the two groups of people trading pups.
“People are exchanging information, they’re exchanging mates, they’re maybe exchanging their wolf pups,” Meltzer tells the New York Times.
While there is strong evidence that the initial domestication event occurred 23,000 years ago, the study relied only on mitochondrial DNA and could be missing the complete picture of domestication events, explains Pontus Skoglund, an ancient canine DNA expert from Crick Institute in London who was not involved in the study, to the New York Times. Likewise, Peter Savolainen, a geneticist at the Royal Institute of Technology, tells Science that the A2b signature has been found in other places in the world and is not unique to dogs in the Americas as the researchers suggested.
Still, the study reveals how the relationship between humans and dogs may have begun and how it may have dispersed across the globe. Perri and her team plan on looking at older dog fossils to gather more evidence.
“We have long known that the first Americans must have possessed well-honed hunting skills, the geological know-how to find stone and other necessary materials and been ready for new challenges,” Meltzer tells Peter Dockrill for Science Alert. “The dogs that accompanied them as they entered this completely new world may have been as much a part of their cultural repertoire as the stone tools they carried.” Recommended Videos Most Popular