When you discover a new dinosaur, first impressions can be everything. When paleontologist Henry Osborn first identified Oviraptor, it was found near a nest of fossilized eggs. Osborn noted how the skull appeared right next to these eggs and theorized the animal had died in the act of preying on the nest, naming it "egg thief."

As it would turn out, this was not the case. Those eggs were actually the raptor's own and the fossil showed the last moments of a mother with her young. Today, Oviraptor is seen as proof of highly developed nesting behavior in some dinosaurs, acting much more like modern birds than previously imagined.

This specimen is a rare cross-section of an Oviraptor fossil recovered from private land in the Hell Creek Formation of Montana. It dates to the Cretaceous Period around 66,000,000 years ago.

Oviraptor ranged in size from that of a modern-day turkey to larger specimens growing up to 26 ft long. These dinosaurs lacked teeth and instead had beak-like jaws. They also had a bony crests on their heads, as well as long feathers on their arms and tails.

Each specimen has been photographed and listed by size in the collection below. All fossils come in a clear acrylic gem jar, set into a glass-topped display case with a photo card serving as statement of authenticity.

"If you were to take a time machine back to the end of the age of dinosaurs… and encountered this animal, your first thought would probably be, 'What a big, weird looking bird,'. I actually think 'chicken from hell' is a pretty good nickname for this thing."

-Matthew Lamanna, Paleontologist at the Carnegie Museum of Natural History

Part of Osborn’s confusion over Oviraptor stemmed from the dinosaur's toothless beak, which was strong enough to break a tough eggshell. More modern studies suggest that Oviraptor used its beak to break open mollusks and clams. If they did, shellfish were only one part of its diverse diet, Oviraptor being one of the few dinosaur omnivores, chowing down on both plants and meat. A recent discovery found the remains of a small lizard where an Oviraptor’s stomach was.

Oviraptor and other dinosaurs like Maiasaura formed a revolutionary new interpretation of dinosaur behavior that began in the 1990s. Before, it was thought that most dinosaurs left their young to fend for themselves. The nesting behavior of these species has made it clear that dinosaur behavior is actually far more complex. Some may abandon their young, but other genera are nurturing parents who watch over their laid eggs.

The Oviraptor's brooding posture mirrored those of modern birds, crouching over the nest and protecting it with its forelimbs. This discovery suggests the behavior evolved far earlier than originally thought, beginning with the non-avian theropod clade. It is also a good reminder that dinosaurs were not movie monsters, but living animals with instincts to protect and care for their young even at the detriment of their own health.

Some Oviraptor eggs have been found with intact embryos fossilized inside. The one pictured here comes from the Hekou Formation in China and was identified in 2021. In ovo skeletons are very rare finds but present important information about the lifecycle and evolution of dinosaurs. Especially interesting here is the tucked posture of the embryo, a behavior previously thought to have originated with birds. This Oviraptor shows the tucked posture may have evolved in non-avian dinosaurs, far earlier than we thought!