For about 20 years, specimen PP-00128 in the earth science collection of the University of Alaska Museum was thought to belong to a fairly old bear. The femur fragment, small enough to be held between two fingers, had been excavated from a site along the southeast coast of Alaska where archaeologists also discovered the remains of fish, birds, mammals and humans dating back thousands of years.
However, recent genetic testing of the sample came as a surprise to scientists, but perhaps not to dog owners: PP-00128 belonged to a loyal canine companion who trotted alongside humans into the frozen new world of the Americas about 10,150 years ago.
Analysis of the remains of the oldest domesticated dog discovered in America, published today in Proceedings of the Royal Society B, not only provides important clues as to when dogs first entered the Americas and the routes they took together with humans to get here, but it also reinforces the very long and deep bond between people and domestic dogs.
“Even if you can’t imagine anything about people’s lives 10,000 years ago, you can still understand the relationship between people and their dogs,” says Carly Ameen, a zooarchaeologist at the University of Exeter who was not involved in the new work.
Paw Print Tracking in America
While this is the oldest physical evidence of domesticated dogs in the Americas, the femur fragment does not necessarily belong to one of the first dogs to arrive from Northeast Asia. In 2018, the burial sites of various dogs in Illinois were found to be around 9,910 years old. With a difference of just a couple of centuries, the title of “major” now hardly belongs to the Alaskan puppy PP-00128. But archaeologists are more interested in the fact that we now have very similarly aged dogs in two very different parts of North America. That means the dogs came to America much earlier, but when did they first arrive?
According to recently revealed genetic evidence, around the time a third of North America was buried under ice during the Last Glacial Maximum (LGM) roughly 26,500 to 19,000 years ago, people increasingly had encounters with gray wolves in Siberia. , where comparatively temperate shelters were provided. prey that both could hunt and eat. These wolves gradually became domesticated dogs sometime between 40,000 and 19,000 years ago. (Ancient wolves that played with humans probably evolved into the friendly dogs of today.)
As part of a multidisciplinary research project looking at the stories of the region’s animals, climate, and environment as the ice sheet invaded and receded, scientists are unraveling the genetics of bones excavated in the region, including those kept at the University of Alaska. Museum. Charlotte Lindqvist, an evolutionary biologist at the University at Buffalo and a co-author of the new study, was interested in what bears were doing back then. One bone, specimen PP-00128, originally excavated from the Lawyer’s Cave site in Alaska’s Blake Channel, was thought to belong to one.
While genetic analysis showed that PP-00128 did not belong to a bear, extraction of the dog’s complete nuclear DNA profile was not possible from the tiny bone fragment. But their mitochondrial DNA was recovered, a small fraction of the entire genome inherited only from the maternal line. The multidisciplinary team’s analysis suggested that the dog belonged to a lineage that split from its Siberian canine cousins no earlier than 16,700 years ago, about the time humans may have been traveling to North America along the coast.
But even this moment in time may not represent the point where some Siberian dogs first followed humans in the Americas. Unless there were very few dogs to begin with, the dog populations that remained in Siberia shouldn’t have all had the same mother as the dogs in the American populations, says Krishna Veeramah, a population geneticist at Stony Brook University who does not. it was. involved with the new job. The dogs in both groups likely shared a common ancestor many generations before, long before they went their separate ways.
In other words, the 16,700 year mark may represent the point at which their genetics diverged, but not necessarily the point at which populations diverged, so the timestamp cannot be used to tell when domesticated dogs they entered America for the first time.
Like the entry of humans to the Americas, the timelines for early canine pioneers remain unclear. (There is no evidence yet to say whether early human migrations included dogs, for example, or whether their four-legged friends arrived a little later.) But the discovery that this domesticated dog lived off the coast of Alaska when the region’s coastal ice had rapidly receded clues as to the routes humans might have taken.
Scientists are eager to know whether humans first moved to the Americas via land corridors between the melting Cordilleran and Laurentide ice sheets, or whether they followed the Pacific coast south. “I’m sure the migration happened both ways,” says Lindqvist, but geological evidence shows that the ice along the coastal route retreated earlier, providing an early access point to the New World.
A ‘swiss army knife’ with skin
Isotopic analysis of PP-00128 revealed that the Alaskan dog was on a diet of things like fish, whale, and seal meat, probably leftovers offered by its human companions. While it’s unclear what this Alaskan dog could have looked like in life, with some reasonable inferences, experts can risk guessing.
Robert Losey, an archaeologist who focuses on human-animal relationships at the University of Alberta and was not involved in the new work, posits that if it were similar to other early Siberian dogs, it would have been something big, maybe 50 to 60 pounds. . “I would expect the dog to behave similarly to our own dogs, to be well adapted to cold environments, and probably also participate in hunting, carrying loads and pulling loads on sleds,” he says. (Humans and dogs have been sledding together for nearly 10,000 years.)
“If you want to get an ancestral American dog, the closest thing you can get is a Siberian or Alaskan husky, a malamute or a Greenland sled dog,” says Angela Perri, an archaeologist at the University of Durham in England who was not part of of the study.
She likens dogs to something of a “Swiss Army knife” for the different purposes they have served people throughout history: as hunters, guardians, alarm systems, bed warmers, and sources of emotional support.
But, Perri notes, ethnographic records tell us that in the Arctic, “when you despair, when times get tough, dogs are used as furs and sources of food.” For dogs entering the Americas, their purpose may have shifted back and forth over time, depending on how difficult conditions were at the time during their former travels.
A draft of ‘ruff’ history
After entering America, these ancient Siberian dogs spread throughout North and South America, where they intermixed with coyotes and wolves, eventually intermingling with dogs that immigrated from elsewhere, including Arctic breeds brought by the Thule people. about 1,000 years ago.
Sadly, the genetic lineage of these ancient dogs was nearly wiped out when European colonialists brought in their own dogs only a few centuries ago, killing the canines that came before through sacrifice and disease. But thanks to genetic work and serendipitous discoveries, his story is not lost in time. And as this latest discovery shows, “There is a huge trove of data in our warehouses and warehouses,” Ameen says.
Given enough time, the vast wilderness of Alaska, through careful archaeological work, will also reveal its secrets about the first arrivals of both humans and their canine companions.
“The answers to everything are there waiting,” says Perri. “There is no animal that has the relationship with humans like dogs, right?”
“The history of dogs is the history of humans,” he adds.