Massive, flightless birds likely roamed the Arctic some 53 million years ago, according to a new study by researchers at the Chinese Academy of Sciences and the University of Colorado Boulder.
In the study, published Friday in the journal Scientific Reports, paleontologists identify two different ancient birds, Gastornis and Presbyornis. Of the two birds, Gastornis is (literally) the bigger discovery.
Although scientists have only found a single toe bone to prove that Gastornis once lived on Ellesmere Island in the Canadian Arctic, the bone matches the toe bones of a Gastornis fossil skeleton found in Wyoming. This toe bone is the only evidence that Gastornis lived in northern latitudes.
Researchers marveled at the similarities between the Arctic Gastornis fossils and those found in Wyoming. "I couldn't tell the Wyoming specimens from the Ellesmere specimen," said Professor Thomas Stidham, one of the study's authors, in a press release, "even though it was found roughly 4,000 kilometers (2,500 miles) to the north."
Based on skeletal evidence, scientists know that Gastornis was built like an NFL lineman, standing around 6 feet tall, and weighing several hundred pounds. Its head was approximately the size of a modern-day horse's head.
If Gastornis were a carnivore, meeting the massive bird could be a daunting prospect. Recent research suggests, however, that the bird was likely herbivorous. Gastornis ate leaves, fruits and seeds.
As with Gastornis fossils, scientists have only found one Presbyornis bone, a fossilized humerus, or upper wing bone. Presbyornis was smaller than Gastornis, and probably looked like today's geese and ducks, with longer, thinner legs.
Although these fossils provide new proof that both birds existed on Ellesmere, the two had been on fauna lists of the island for some time. This study is the first time the bones had been described.
"We knew there were a few bird fossils from up there, but we also knew they were extremely rare," said Jaelyn Eberle, one of the study's authors.
Today, Ellesmere is one of the coldest places on Earth, with winter temperatures dipping to negative 40 degrees Fahrenheit. Predictably, bird fossils are rare in the Arctic.
Yet the island is a fossil treasure box for paleontologists. Ellesmere was first explored by researchers in the 1970s. Since then, scientists have found fossils from fauna as diverse as crocodilians to fish to primates. Millions of years ago, they say, Ellesmere was probably more similar to the southeastern United States than Alaska.
The study's authors say that understanding Ellesmere's warmer periods could help scientists predict what climate change could bring to the world's current cold places.
"I'm not suggesting there will be a return of alligators and giant tortoises to Ellesmere Island anytime soon," said Eberle, "but what we know about past warm intervals in the Arctic can give us a much better idea about what to expect in terms of changing plant and animal populations there in the future."