As much research as scientists have done so far on dinosaur fossils, one would expect there is little left to be discovered about the ancient creatures that roamed the Earth billions of years ago. A new study conducted on dinosaur eggs published on Monday, January 2nd, in the journal Proceedings of the National Academy of Sciences, however, points to several clues about the reptiles that have, so far, gone unnoticed.
While dinosaur egg fossils are hard to come by, unhatched dinosaur embryos are even more scarce. By examining the embryo’s teeth, paleontologists were able to determine that some species spent between three to six months incubating. This discovery led scientists to believe that the long incubation periods required by some species also played a part in the mass extinction following the meteor impact nearly 65 billion years ago.
By studying fossilized egg shells and a dinosaur embryo, Gregory M. Erickson and his team of researchers from the Florida State University were able to determine some interesting facts about dinosaurs’ behavior, evolution, and how they went extinct.
Incubation Time
Generally, bird hatchlings emerge from their shells after 11 to 85 days. Assuming that birds are dinosaurs’ closest living relatives, paleontologists expected the extinct creatures had similar incubation rates. However, by analyzing a Protoceratops andrewsi embryo, the team of researchers concluded that the hatchling took three months to incubate. At the same time, a representative of a duck-billed dinosaur, Hypacrosaurus stebingeri took almost twice as long.
Dinosaur Eggs Color
While dinosaur eggs differ in size and texture, some species were able to lay blue-green colored eggs. Experts believe this helped female dinosaurs protect their eggs by camouflaging them among leaves. Another theory suggests that dinosaur parents relied on the distinctive blue-green hue of their eggs to spot imitations snuck into the nest by charlatans. Similar behavior can be observed in modern robins.
Assigning Gender
Looking at several samples of fossilized dinosaur egg shells, researchers are now able to figure out an adult fossil’s sex. As it turns out, female dinosaurs produced a type of tissue known as medullary bone for a brief period before laying the eggs, in order to line the marrow cavities in her bones. The supply of calcium was used in eggshells by the expectant mothers, according to the scientists. This finding will lead paleontologists to better determine the sex of the fossils they study. Prior to the discovery, the practice of assigning gender to a dinosaur fossil has proved surprisingly difficult for the scientific community.
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