While it’s long been known that at various points in the past the Arctic (and the Arctic Ocean) has been considerably warmer, and home to animals such as crocodiles, camels, tropical birds, etc, there is still quite a lot that remains unknown about the past history of the region. The recent discovery of fossil remains of a giant 6-foot tall flightless bird known as Gastornis — a relative of similar birds mostly known from fossil remains found much further south — is a case in point.
Picture a giant, likely very loud, bird with a head the size of a horse’s and a beak big and powerful enough to crack your skull open… Walking around during the 24-hour daylight of the Arctic midsummer. Or perhaps during the permanent midnight of the Arctic winter (which was still quite a warm season, at the time).
Quite an image right? The past was quite strange — probably far more so people can today readily imagine (or maybe remember is a better word?).
The fossil remains found on Ellesmere Island date back to around 53 million years ago, and aren’t very extensive (a toe bone) but are “nearly a dead ringer to fossil toe bones from the huge bird discovered in Wyoming and which date to roughly the same time.”
The Gastornis (formerly Diatryma) fossil from Ellesmere Island has been discussed by paleontologists since it was collected in the 1970s and appears on a few lists of the prehistoric fauna there, said Professor Thomas Stidham of the Chinese Academy of Sciences in Beijing. But this is the first time the bone has been closely examined and described, he said. Gastornis fossils also have been found in Europe and Asia.
“We knew there were a few bird fossils from up there, but we also knew they were extremely rare,” stated CU-Boulder Associate Professor Jaelyn Eberle.
Here’s more via a recent press release:
In addition to the Gastornis bone from Ellesmere, another scientist reported seeing a fossil footprint there, probably from a large flightless bird, although its specific location remains unknown, Eberle said.
About 53 three million years ago during the early Eocene Epoch, the environment of Ellesmere Island was probably similar to cypress swamps in the southeast US today, Eberle said. Fossil evidence indicates the island, which is adjacent to Greenland, hosted turtles, alligators, primates, tapirs and even large hippo-like and rhino-like mammals. Today Ellesmere Island is one of the coldest, driest environments on Earth, where temperatures can drop to minus 40° degrees Fahrenheit in winter.
Originally thought to be a fearsome carnivore, recent research indicates Gastornis probably was a vegan, using its huge beak to tear at foliage, nuts, seeds and hard fruit. A second Ellesmere Island bird from the early Eocene also is described by Stidham and Eberle in the new paper. Named Presbyornis, it was similar to birds in today’s duck, goose and swan family but with long, flamingo-like legs. The evidence was a single humerus, or upper wing bone, collected by the same paleontology team that found the Gastornis bone.
Stidham compared casts of Presbyornis bones excavated in ancient Wyoming to the single bone from Ellesmere Island, including all of the marks for muscle attachments. “I couldn’t tell the Wyoming specimens from the Ellesmere specimen, even though it was found roughly 4,000 kilometers (2,500 miles) to the north,” he said. While the diversity of plants and animals on Ellesmere was surprisingly high in the early Eocene, one of the biggest challenges to life on the island may have been the Arctic winters, said Eberle.
“Since Ellesmere Island is high above the Arctic Circle, the lights still went out there for several months of the year, just as they do today.”
Which makes one wonder whether Presbyornis was migratory, or sedentary.
“Given the fossils we have, both hypotheses are possible,” he continued. “There are some sea ducks today that spend the winter in the cold, freezing Arctic, and we see many more species of waterfowl that are only in the Arctic during the relatively warmer spring and summer months.”
The abstract for a research paper describing the fossil remains can be found here.
Image Credit: Marlin Peterson