At about seven ounces and close to the shape of a potato, the eggs were relatively small and didn’t give Erickson a lot to work with. However, a few other specimens gave him plenty of work to do.
These dino egg fossils had been discovered in the Canadian province of Alberta and belonged to the species of dinosaur known as the Hypacrosaurus Stebingeri, which is sort of like a cross between a T-Rex and a duckbill dinosaur. It was a bipedal herbivore and usually grew to about nine meters in length.
Erickson came to wonder if dinosaur embryos could be studied using a similar method. He started reaching out, and contacted experts at Canada's University of Calgary and the American Museum of Natural History in New York.
He wondered if there was a way to test his theory. Despite how rare fossilized dinosaur embryos are, both institutions decided they were able to assist Erickson in his research.
At the American Museum of Natural History, researchers found the eggs from the Gobi Desert in Mongolia, which according to experts at the time belonged to the species Protoceratops Andrewsi, which is a close relative of the Triceratops.
The Protoceratops Andrewsi doesn't have the three horns so famous among dino fans but did sport the fan of bone and horn that came off the head like a headdress.
The duck-billed Hypacrosaurus laid eggs that weighed almost nine pounds. They have the same proportions as a volleyball.
While they were much bigger and had specimens entirely different from those Erickson had started his study on, he found plenty of exciting material.
Within both sets of eggs, researchers had discovered fossilized embryos. The question remained: could Erickson use a dentin analysis to learn about the ages of these dinosaurs?
Could this teach us about the time it took them to hatch? Leading a team of researchers, Erickson got to work on finding out the answer.