Her life was short. Scientists estimate she lived for about six or seven weeks in the underground den, before it collapsed around her. This tragedy and the permafrost that preserved her body are the reasons we know of this wolf pup’s existence approximately 57,000 years later. Zhùr, or ‘wolf’ in the Hän language, is the subject of a paper published today in Current Biology.
Her preservation is exquisite: from the details of her face and lips, to the tiny claws on each paw and her sweet ginger fur. Unlike mere bones, the fluffy body of Zhùr gives us a tantalizingly vivid look at an animal that co-existed with woolly mammoths and other creatures that have since gone extinct.
But that soft, ginger look was not how she appeared when her body initially emerged from the ground in 2016. And given the circumstances of her unintended excavation, it’s remarkable she was found at all. Neil Loveless, the fourth-generation placer miner who found her, agrees.
Placer mining—a type of mining for gold—uses just water and gravity, according to Loveless, rather than the chemicals used in larger operations that mine through much harder rock. Enormous water cannons are pointed at cliffs of permafrost, thawing them out so that sediment (and gold between the rocks) falls to the ground below.
“Placer mining is typically a closed loop system,” Loveless wrote in an email, “so the sediment and water is not going back into a stream. Sediment is being settled out then removed from the pond and spread around for reclamation.”
A few times a day, the cannons will be shut off, enabling miners to walk around the mud and water to look for fossils, a common find in their work.
“I just happened to be on one of those walks when I saw what I thought was a chunk of moss,” Loveless said in a phone interview, “but it didn’t quite look right, so I gave it a kick and that kind of moved it.”
It was a shriveled mass of… something. Cognizant of the history of the area, in which non-native miners in the 1800s dug down into the permafrost searching for gold, Loveless said, “I thought it must have been maybe a puppy that had fallen down into the shaft about 100 years ago, but that was just my quick assumption because it was so intact and in such good shape.”
He called the local paleontologists just in case, brought it home, and stored it in his freezer to prevent further decay. He remembers thinking: “There’s no way this thing’s old.”
Grant Zazula, Government of Yukon paleontologist, and his colleagues initially tested the wolf pup using radiocarbon dating.
“When we got the date back and learned that it was over 50,000 years old, we’re like, ‘Ok. We’ve got a story here, and we’ve got to do something.’ And that’s when I made the phone call to [Julie Meachen] right away,” Zazula said in a video chat.
Meachen, associate professor at Des Moines University and lead author of the new paper, has significant expertise in Pleistocene predators like wolves and saber-toothed cats. She described their findings in a virtual presentation at this year’s annual meeting of the Society of Vertebrate Paleontology. Beyond eyelids, skin, and fur, Zhùr’s genitalia and intestines remain intact, making her the oldest, most complete wolf pup mummy yet found.
The team used about 10 follicles of hair to further determine her age through ancient DNA. Paper co-author Molly Cassatt-Johnstone, a research associate at the Paleogenomics Lab at University of California, Santa Cruz, explained that the permafrost helped preserve the pup’s DNA, enabling them to further research her ‘molecular clock.’
“In genetics, [a molecular clock is] based on the accumulation of mutations in the DNA over a period of time,” Cassatt-Johnstone wrote in an email. “All species have a molecular clock, and different areas of the genome will accumulate mutations at different rates. So, depending on where you are looking and for what, the molecular clock rate will differ.”
Zhùr’s mitochondrial DNA—a type of DNA that is prolific in each cell—offered them the chance to see how she was “related to a greater genetic diversity of the species.” They found that her mitochondrial genome was not a direct match to the clade of gray wolves that exist there today. It was, however, a match to a clade comprising wolves from North America and Eurasia, with a common ancestor they estimate to have lived between 86,700 and 67,500 years ago. In other words, if her mitochondrial genome doesn’t match the wolves in the area now, this suggests that at some point some wolf populations in the region were wiped out.
Isotopic analysis provided more insight into the pup’s diet. What they discovered surprised them: Her meals indicated they had been pulled from local rivers.
“Mostly when you think about wolves—Pleistocene wolves especially—you think about them being megafaunal specialists, [such as] eating mammoths, woolly rhinos, [or] bison,” Meachen said in a video chat. “Bison is the thing I would really expect her to have been eating. The fact that she was specializing on aquatic resources was a little surprising.”
Matthew Wooler, professor at the University of Alaska Fairbanks and co-author, remarked that this discovery occurred when they compared Zhùr’s isotopes to those of extant wolves in Alaska and Canada.
“Another thing about how isotopes work, certainly for an infant or a wolf pup like this, is that, by proxy, you’re also saying what the mother ate, because the mother was feeding the pup,” Wooler said in a video chat.
The bone structure, as seen through radiographs, also contributed to determining her age. The team assumed her bone growth compares to that of domestic dogs, in which case the complete ossification—or the process by which bone forms and hardens—of certain limb bones indicates she was at least 6 weeks old. The lack of complete ossification in others indicates she was not 8 weeks old.
The scientists were even able to determine the possible season of her death through stable isotopic analysis. If, as Alaskan wolves do today, ancient wolves in the Yukon (Beringian wolves) gestated for two months after breeding in April, wolf pups would be born in the summer. The team suggests she died in either July or August—an interesting detail, given her discovery almost 60,000 years later in July 2016.
“She was probably killed instantaneously from the den collapse,” Meachen said. If she had merely been trapped in the den, “her ultimate cause of death probably would have been starvation.”
The story of this wolf pup doesn’t begin or end with the science. Zhùr’s name means ‘wolf’ in the language spoken by members of Tr’ondëk Hwëch’in, a First Nation community who have lived in that area of the Yukon far longer than their non-native counterparts. To those in the Tr’ondëk Hwëch’in, Zhùr’s significance is more than just an outstanding discovery: She is considered family. Reverence for the land and everything on it is an integral facet of this First Nation, whose clans include the Wolf Clan.
Debbie Nagano, Tr’ondëk Hwëch’in heritage director, explained that no one in the community “named” the wolf pup. Zhùr is a wolf, hence her name is “Zhùr.”
“If you value what people think and believe as much as their physical connections to the world, [then] yes, of course, she’s a family member,” Jody Beaumont, Tr’ondëk Hwëch’in traditional knowledge specialist said of Zhùr in a phone interview. “I think some of the people here would look at you funny if you questioned that at all. She’s a family member on so many levels. Part of it is what she represents, and, to me, it’s that long-standing commitment [to the land and all living creatures.] Making a commitment to another living being overlays a whole approach to life. You don’t literally have to be that blood relative. Some of the most important parts of [our] culture here [include] having that bigger vision. And, I think, a bigger sense of responsibility and connectedness. It’s not just [having a connection to] your family; it’s [being connected to] everything altogether.”
That notion of connectedness seems to pervade every step of this discovery, from the miners to the paleontologists to the members of the First Nation, and it is a nod to the uniqueness of the Yukon. Just as the placer miners connected with Yukon paleontologists to inform them of their discovery, so, too, did the paleontologists connect with members of the Tr’ondëk Hwëch’in. Although rooted now in Yukon law, one gets a genuine sense of welcome collaboration between them. Zazula explained that members of the First Nation have been involved in the research from the start. All three of these communities have worked together in this find, each with their own perspectives but all with the same ultimate goal: to celebrate and understand this wolf pup.
This hasn’t always been the case.
Whereas the Tr’ondëk Hwëch’in had always lived near the Klondike River without defined borders, this began to change rapidly when prospectors learned of gold in the 1800s. “Klondike” was a non-native mispronunciation of Tr’ondëk. Jumping from 400 non-natives to a staggering 30,000 at its height, the Gold Rush changed the landscape and pushed the First Nation out of its own home. After years of struggle, the Tr’ondëk Hwëch’in became an official self-governing First Nation in 1988. Agreements related to this were signed 10 years later in 1998.
When the wolf pup was first revealed to the public, it was done at the Dänojà Zho Cultural Centre. Beaumont and Nagano explained that this event brought in many people from the area, some of whom had never set foot in the Cultural Centre beforehand.
“It’s almost like this wolf pup has been waiting to come back into people’s consciousness or into their lives,” Beaumont mused by phone. “I keep wondering: Why did that wolf appear now? I just think it’s at a time when people are ready, even in the mining community who unearth many of these beings. They see the value in this wolf, too.”
“Everybody could get together around this really meaningful story,” she continued. “It was sort of like everyone in the Yukon could feel really proud about how it was all handled. If this was 20 years ago, this would not have been handled in the same way. And it really speaks to the growth that a lot of people have had in the community, as community members with all these different backgrounds and ideas and perspectives.”
For everyone involved, the excitement and awe caused by Zhùr is unanimous.
“We see bones all the time. We work with bones. We have collections of bones. We dig up bones,” said Zazula. “But when you have something with flesh and skin and hair, it just makes the job real. When you’re staring at this little [pup, you realize:] ‘This was an animal that was running around 60,000 years ago, eating salmon in this landscape that’s familiar yet totally strange.’”
Jeanne Timmons (@mostlymammoths) is a freelance writer based in New Hampshire who blogs about paleontology and archaeology at mostlymammoths.wordpress.com.