More than 50 million years ago, Canada's Arctic was a warm, wet place, home to alligators, giant tortoises and — as it now turns out — giant, flightless birds.

A new study by scientists  from the Chinese Academy of Sciences in Beijing and the University of Colorado Boulder has confirmed that a single fossilized toe bone discovered in the early 1970s on Ellesmere Island in what is now Nunavut belonged to a species called Gastornis.

The bird, which scientists believe was as tall as a person, boasted a head the size of a horse's and weighed several hundred pounds, roamed during the steamy Eocene epoch, about 50 million to 53 million years ago, feasting on foliage, nuts, seeds and hard fruit.

"Certainly that toe is enough to say, 'Yep this was a great big bird,'" co-author Jaelyn Eberle, an associate professor in geological sciences at the University of Colorado Boulder, told CBC News.

The toe — a rare find, as bird bones don't tend to hold up as well as those of mammals and reptiles — was found in the '70s by an Arctic paleontology team consisting of Mary Dawson, Robert (Mac) West, Howard Hutchinson and Malcolm McKenna. 

"It was discovered, it was listed in fossil lists, but was never described and was actually kind of lost in the collection," Eberle said.

Lost, that is, until Eberle and co-author Thomas Stidham of the Chinese Academy of Sciences decided to study it. They compared the toe with Gastornis fossils from Wyoming dating back to the same period. Gastornis fossils have also been found in Asia and Europe. 

"I couldn't tell the Wyoming specimens from the Ellesmere specimen, even though it was found roughly 4,000 kilometres to the north," Stidham said in a press release.

Using the same technique, the scientists were also able to identify another fossil from the same expedition as Presbyornis, something like a long-legged duck or swan.

"It's a very diverse Arctic fauna," Eberle said. "It's exciting. I think there's probably more discoveries waiting to happen, both out in the field, but also in the lab and in the collections." 

Studying the past to predict the future

These discoveries help shed light on what the Arctic was like during the Eocene epoch, when Ellesmere Island was most likely a hot, swampy environment, home to giant turtles, alligators, primates and hippo-like beasts. 

That, in turn, gives us some idea of what to expect as climate change dramatically alters the northern landscape, Eberle said. In order to develop accurate climate models to predict the future, scientists need solid, measurable data from the past — especially from previous periods of warmth in the Arctic.

"I don't think it's going be a surprise to anyone that the permanent ice is going away and there's a real chance it will be gone in my lifetime," she said.

That doesn't mean Nunavut will once again become overrun with alligators, giant tortoises and massive vegan birds, Eberele said, but wildlife and treelines are moving farther north, and long-abandoned migratory routes between North America and Asia could open up again.

"I'm not predicting alligators in the near future, but I do think there are going to be changes," she said.