A hatchling Protoceratops andrewsi fossil from the Gobi Desert in Mongolia. Credit M. Ellison/American Museum of Natural History.
Exciting new information about the reproductive life of nonavian dinosaurs.
For decades now, the drumbeat of dinosaur news has been their similarity to birds. They were warmblooded! They had feathers! And they’re still around, because birds are actually dinosaurs.
All true, but those that were nonavian dinosaurs, as they are now called, were not all beak and tweet. They were closely related to other living reptiles like crocodiles, and new findings about how long their eggs took to hatch bring that point home.
Scientists reported on Monday that by using a new technique on exceedingly rare fossils of unhatched dinosaur embryos, they determined that those embryos took twice as long to hatch as bird eggs of a similar size. The embryo of a large duck-billed dinosaur took at least six months to hatch, and the eggs of larger dinosaurs may have taken even longer.
The long incubation times complicate thinking about dinosaur behavior. While some kinds of dinosaurs may have tended their eggs and young, for others the difficulty of hanging around for most of a year to watch buried eggs would have been too much.
It seems some duck-billed dinosaurs did wait the long time necessary for the eggs to hatch, because there is evidence they fed their young some time after hatching -- click --
Maybe a lot of these eggs were incubated internally for much longer prior to actual laying?