In 2011 and 2015, two approximately 14,000-year-old pups were pulled from northern Siberia’s permafrost roughly 25 miles (40 kilometers) from the village of Tumat. Within the same layers of icy soil, researchers found woolly mammoth bones with evidence of human processing. This led some to wonder whether the “Tumat Puppies” may have been tamed wolves or even early dogs waiting around for scraps at a prehistoric butchering site.

In a new study, an international team of researchers analyzed the pup remains in search of possible links to mammoth-related human activity that might support the theory. To the disappointment of some, however, they concluded that the pups had no association with mammoth butchering—and, by extension, no clear link to human activity—and were actually very similar to modern wolves.

To reach this conclusion, the University of York-led team analyzed genetic data pulled from the contents of the pups’ gut, in addition to “chemical fingerprints” in their teeth, bones, and tissue, to determine if anything about their diet could be linked to human activity, according to a university statement.

“The Tumat Puppies, two permafrost-preserved Late Pleistocene canids, have been hypothesized to have been littermates and early domesticates due to a physical association with [presumed] butchered mammoth bones,” the researchers wrote in the paper published Thursday in the journal Quaternary Research. With “no evidence of mammoth consumption,” however, their data does not “establish a link between the canids and ancient humans.”

In other words, if the pups had been early dogs or tamed wolves hanging out alongside humans at a mammoth-butchering site, they very likely would have eaten some mammoth meat—but the researchers found no evidence of this. They did, however, discover that their last meal included woolly rhinoceros.

Their analysis revealed that the Tumat Puppies “were littermates who inhabited a dry and relatively mild environment with [mixed] vegetation and consumed a diverse diet, including woolly rhinoceros in their final days,” the researchers explained in the study. This came as a surprise, given that woolly rhinos—even baby woolly rhinos—represented an ambitious prey for the significantly smaller wolves to take on.

As such, these Ice Age wolves may have been bigger than today’s wolves. An adult pack probably hunted down a young woolly rhino and fed it to the pups, and they must have died shortly after the meal, as researchers found a piece of undigested woolly rhinoceros skin in one of their stomachs. As for their diverse diet, the analyses revealed that they consumed both meat and plants, akin to modern wolves. Since they bear physical evidence of having nursed, they were likely still receiving milk from their mother, as well. Fossilized plant remains in their gut also provided insight into their prehistoric environment, suggesting they lived in a region with diverse habitats and ecosystems.

“We have an insight into their breeding behaviours too,” Nathan Wales, a co-author from the University of York’s Department of Archaeology, said in the statement. “The pair were sisters and likely being reared in a den and cared for by their pack—all common characteristics of breeding and raising of offspring in wolves today.” Furthermore, the findings support previous genetic research indicating that the cubs were members of a now-extinct wolf population completely unrelated to modern dogs.

One reason researchers had suggested the pups were early dogs is that their fur is black—a mutation previously thought to exist only in dogs. The study clearly challenges this theory, further complicating the mystery of the origin of dogs, Anne Kathrine Runge, a co-author of the study from the University of York’s Department of Archaeology, explained in the statement.

“Whilst many will be disappointed that these animals are almost certainly wolves and not early domesticated dogs,” Runge explained, “they have helped us get closer to understanding the environment at the time, how these animals lived, and how remarkably similar wolves from more than 14,000 years ago are to modern day wolves.”

The paper comes in the wake of a highly contentious debate within the scientific community about Ice Age wolves, specifically whether biotech company Colossal Biosciences’ genetically-edited canines are resurrected dire wolves, or just genetically-modified gray wolves.