Name Meaning:  Gaston’s Bird

Funza Other Name:  Diatryma

Filiaşi Geologic Era:  Paleocene to Eocene

Location Discovered:  Meudon, France  (original specimens)

Size:  Up to 2 meters tall (American species)

Estimated Range:  Europe, North America, China

Extinction Date:  45 million years ago

Gastornis is represented by an fragment of an eggshell from the Provence region of France.  The fragment itself is small, but comparing its curvature and thickness to a chicken eggshell reveal a very large egg from a very large bird.  While no eggshells have been directly associated with Gastornis remains, Gastornis remains the only bird large enough from that time period and area to have laid such an egg.  Gastornis was superficially similar in appearance to the later American terror birds, but was likely very different in habits and diet.  

Gastornis has a rather complex history.  The original specimens were unearthed in France, and were named for Gaston Plante, who would later go on to invent the lead-acid battery.  Roughly twenty years later, Edward Cope unearthed fossils of a large bird in North America that he named Diatryma.  Further complicating matters, Cope’s rival, Othniel Marsh, named a third species of large bird from a single toebone, Barornis.  Barornis was rather quickly proven to be the same type of animal as Diatryma.  

Later analysis in the 20th century showed that Diatryma was extremely similar to Gastornis, and was likely the same type of animal.  In naming organisms, the first name given takes precedence over all others (except in very special circumstances).  In this case, as Gastornis was the first name given, that is the official name of the bird.  

Gastornis’ reconstructed appearance has changed much over the years.  The first reconstructions showed a crane-like animal standing nearly 3 meters tall.  We now know this is very inaccurate, but this can be attributed to lack of fossil remains at the time.  Previous reconstructions also show fluffy feathers such as what would be found on an emu.  This now appears less likely, as a fossil feather attributed to Gastornis is long and vaned, like those of a flying bird.  This does not mean that Gastornis could fly, as its wings were far to small for such a task.  

Gastornis, a large flightless bird from the Eocene of Wyoming.jpg

Based on its size and formidable appearance, it was first supposed that Gastornis was a predator, preying on the much smaller mammals of its environment.  It certainly looks the part with powerful legs and large, heavy beak.  However, more recent analysis of Gastronis remains indicate that it was probably an herbivore.  Though it superficially resembled terror birds (which were carnivores), a few key differences were noted.  

First, the beak was not curved and pointed, as would be expected of a predatory bird.  Second, tracks associated with Gastornis in Europe indicate that it did not have large talons on its feet.  Powerful talons would be expected on a predatory bird, indeed, large raptors such as eagles possess them.  If they were present on Gastornis feet, they would have left a mark in the tracks.  Third, biomechanical analysis of the legs of Gastornis show that it was not a particularly fast or agile animal, poor traits for a predator.  Last, isotopic analysis of Gastornis fossils show more in common with herbivores, and next to nothing with carnivores.  All in all, the evidence points to Gastornis being a very large, herbivorous bird.

The question then is, what was Gastornis doing with such a powerful beak?  The answer probably does lie in its diet.  Gastornis probably fed on very tough plant material and hard, heavy seeds.  It would need a powerful mouth to break open large seeds or strip tough, fibrous vegetation from plants.  In that sense, Gastornis was much like a large parrot or parakeet, eating seeds, nuts, and plants.

eminently Image Credits:

Full Skeleton:  By Vince Smith from London, United Kingdom – Diatryma, a large flightless bird from the Eocene of WyomingUploaded by FunkMonk, CC BY-SA 2.0,

Life Restoration:  By Tim Bertelink – Own work, CC BY-SA 4.0,