Oviraptor

About Oviraptor

Characteristics and Ecology of Oviraptor

Oviraptor was a small bipedal theropod that lived in Asia (such as the present-day Gobi Desert in Mongolia) during the Late Cretaceous period. Since clear traces of feathers have been found in fossils of closely related dinosaurs, it is believed that Oviraptor was also completely covered in bird-like feathers.

Its most distinctive feature is a strong, toothless "beak". In particular, there was a bony projection in the center of the upper jaw, creating a structure perfectly suited for crushing hard objects when biting down with the lower jaw. Its forelimbs were relatively long, with three slender, delicate fingers ending in sharp claws.

Regarding the use of this beak, there was once a theory that it was used to crack and eat hard-shelled mollusks. However, because a lizard skeleton was found near the stomach region of an Oviraptor, and gastroliths have been found in close relatives, it is now considered to be omnivorous. It seems it used its powerful beak not only to grind hard plants like seeds but also to prey on insects and small vertebrates.

Also, the structure of its skull suggests that its eyes protruded to the sides, giving it excellent vision. Rather than aiming at prey stereoscopically, this was suitable for securing a wide field of view to keep watch on the surroundings.

Stigma and History of Discovery

The name Oviraptor was born from a major misunderstanding in the history of dinosaur research.

In 1923, an expedition from the American Museum of Natural History discovered the first fossil in the Gobi Desert of Mongolia. At this time, the skull was found lying over a nest of eggs, just 10 centimeters above them, which were thought to belong to Protoceratops. The describer, Henry Osborn, initially proposed the name "Fenestrosaurus," but in 1924, thinking it was a thief targeting Protoceratops eggs, he named it "Oviraptor" (egg thief).

However, in the 1990s, this idea was overturned. Fossils of adult Oviraptorids sitting on egg nests like birds were discovered one after another in Mongolia and China. As more conclusive evidence, skeletons of Oviraptorid babies (embryos) were found inside the eggs previously attributed to Protoceratops.

In other words, it turned out they were not trying to steal and eat someone else's eggs, but were devoted parents trying to incubate and protect their own eggs. The stigma of "egg thief" they bore for about 70 years was a false accusation. The specific name "philoceratops" (lover of ceratopsians) now has an ironic ring to it.

Oviraptor's "True Identity": A Mix-up

Although Oviraptor has been cleared of the "egg thief" stigma, there is actually more to the story. The figure with a splendid crest incubating eggs, which we often see in encyclopedias and museums, is strictly speaking not an Oviraptor.

The specimen originally named "Oviraptor" (holotype) has a poorly preserved skull that was crushed from the side. Later research has shown that the real Oviraptor likely had a slightly longer snout and did not have the high, round crest we imagine.

On the other hand, well-preserved fossils found incubating eggs were discovered in subsequent research to have different characteristics from Oviraptor and were given another genus name, Citipati. In other words, "that figure warming the eggs" is mostly of the closely related Citipati.

For this reason, restorations and skeleton photos of "Oviraptor" in general encyclopedias are actually depicting "Citipati" in most cases. The accurate appearance of the real Oviraptor still remains largely shrouded in mystery.

Bird-like Reproductive Behavior

Fossils of Oviraptor and its relatives (Oviraptorosaurs) are important existences that teach us the "evolutionary process of reproductive behavior" leading from non-avian dinosaurs to modern birds. Recent research has continually revealed that they had an ecology surprisingly similar to birds.

• Incubating eggs with body heat (contact incubation): It was once thought they warmed their eggs with the heat of the soil like crocodiles, but analysis of fossil eggshells revealed their eggs were incubated at high temperatures of 35-40 degrees Celsius. This suggests the parent had a high body temperature like a bird and sat directly on the eggs to warm them.
• Asynchronous hatching: A 2021 study confirmed a gap in the growth stages of babies within eggs in the same nest. This indicates that they did not all hatch at once, but hatched sequentially over a period of days to weeks.
• Tucking posture: Modern bird chicks adopt a posture called "tucking" just before hatching, pushing their heads under their wings and curling up. Well-preserved fossils show that Oviraptorid babies also took exactly the same posture inside the egg.

In this way, the highly advanced behavior of incubating eggs with body heat to promote growth had already been established during the age of dinosaurs, long before the birth of birds. Oviraptor is an existence that lets us feel the process of evolution from dinosaurs to birds.

Oviraptor Stamp and Fossil Gallery