Dinosaur Eggs-citement

Scientists have found dinosaur eggs, with their shells on, inside a female dino fossil.


This fossil egg, one of two found inside a female dinosaur's body, still has its shell.

Y.N. Cheng

Dinosaurs may have become extinct, but they sure didn’t disappear.

Scientists recently announced finding dino bones with scraps of cells and blood vessels preserved inside them (see “Dino Flesh from Fossil Bone”). Now, a different group of paleontologists has found dinosaur eggs, with their shells on, inside a female dino fossil. It’s the first discovery of its kind.

Researchers from Canada and Taiwan found bones from the lower part—the pelvis—of a female dinosaur in southern China. Based on measurements of surrounding dirt, the dinosaur lived between 100 million and 65 million years ago.

Two potato-shaped eggs filled the inside of the dinosaur’s pelvis, which suggests that the Mama dino was just about ready to lay them when she died. Each egg was 17 centimeters (6.7 inches) long. Whatever was inside the eggs had long since disintegrated.

There weren’t enough remains to identify the species of dinosaur, but the researchers can tell that it belonged to a group called oviraptorosaurs. Because the dino’s eggs filled its pelvic cavity, the scientists conclude that this type of dinosaur could carry only two eggs at a time.

And because the eggs were of similar size, the dinosaur probably produced them at the same time. These traits make the dinosaur similar to both modern reptiles and modern birds.

The new find adds to previous evidence about the egg-laying habits of oviraptorosaurs. Scientists have found oviraptorosaur nests in Asia that held rings of eggs grouped into pairs. Fossil evidence suggests that oviraptorosaurs spent lots of time during the nesting season laying their eggs, two at a time, while crouching in the center of their nests.

With each new fossil discovery, it’s becoming easier to picture what the world was really like when dinosaurs lived.—E. Sohn

Going Deeper:

Perkins, Sid. 2005. Egg-citing discovery: Dinosaur fossil includes eggshells. Science News 167(April 16):243. Available at http://www.sciencenews.org/articles/20050416/fob1.asp .

Sohn, Emily. 2005. Dino flesh from fossil bone. Science News for Kids (March 30). Available at http://www.sciencenewsforkids.org/articles/20050330/Note2.asp .

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