This is the largest of all Eocene birds, Gastornis, a half-pile of muscle and feather as tall as a grown man.
— Allen, about Gastornis

Gastornis (name meaning "Gaston's Bird"), also known as Diatryma, is a genus of large, prehistoric, flightless predatory died that originated during the Paleocene and the Early Eocene epoch in what is now Germany, France, and North America. It was smaller but more robust than the terror bird Phorusrhacos.

Strangely, it's been questioned whether this animal was a herbivore or a carnivore or even an omnivore. Nonetheless, Gastornis was the apex predator for the Paleocene and much of the Eocene that ruled over the plethora of small animals that had survived the K-T Extinction of the dinosaurs 65 MYA, dying out only when larger mammalian predators such as Hyaenodon evolved.


Era & DiscoveryEdit

Gastornis lived during the Early Eocene period, over 50 million years ago. It was the apex predator of its time and shared its environment with creatures such as Propalaeotherium, Leptictidium, and Ambulocetus.

Gastornis was first described in 1855 from a fragmentary skeleton. It was named after Gaston Planté, described as a "studious young man full of zeal", who had discovered the first fossils in Argile Plastique formation deposits at Meudon near Paris.

Physical AttributesEdit

The largest of all predatory Eocene birds, Gastornis stood about 6 feet (2 m) tall, as tall as a grown human, and weighed 1000 lbs., making them the second largest flightless bird ever to exist, after the Pleistocene Terror Birds Phorusrhacos. Gastornis were large, fairly thickly-built birds with heavy, stocky heads and a 45 cm skull and beak, shaped like a hatchet. The beak, although very large, was not hooked like with other terror birds such as Phorusrhacos

Although Gastornis was the biggest land creature of its time, it had a relatively short neck and thick legs, as opposed to terror birds of later times; in fact, despite the superficial similarities, Gastornis' closest relatives were ducks and chickens, while the terror birds (phorusracids) are actually closely related to cranes, seriemas, etc.

Gastornis feathers came in a variety of bright colours; most individuals had cream undersides and turquoise to green bodies. The skin around their faces was red and wrinkly. Although the wings - and companion feathers - of Gastornis were underdeveloped, similar to trimmed chicken wings, they were still better developed than those of Phorusrhacos.

Gastornis, much like Phorusrhacos, also had crests of colored plumage on the back of their heads. This plumage was duller and less apparent than on the Phorusrhacos.

Behavior & TraitsEdit

1000px-WWB1x1 GastornisCheckingEgg

Female Gastornis with an egg

Gastornias were solitary creatures, only getting together during mating season. Gastornis was most likely an ambush predator, lying in wait to attack animals like Propalaeotherium. When female Gastornias laid eggs, the had to wait two months for them to hatch. These birds were also fiercely territorial and when another Gastornias (whether it be male or female) got to close, the mothers moved to protect their nest.

Since the great extinction of the dinosaurs, birds like Gastornis had been a success like all mammals but, what was more, they grew large – enough so to take over the role of the predatory dinosaurs, from as small as the lethal Velociraptors to as giant as even the terrifying Tyrannosaurus rex.



  • Gastornis is the second largest flightless bird brought to the park.
  • The sound effects of Gastornis are typical bird chirps as well as vulture sounds.