70-Million-Year-Old Dinosaur Embryo Showing Prehatching Behaviors That Link Non-Avian Dinosaurs to Modern Birds

Dinosaur embryo curled inside its egg in a bird-like hatching position, showing prehatching behaviours that link non-avian dinosaurs to modern birds. Illustration by the author.

Image Credit: PubMed Central

A new fossil discovery gives us a fascinating glimpse into the lives of dinosaurs long before birds existed. Scientists have found a remarkably well-preserved 70-million-year-old dinosaur embryo inside an egg in southern China. The embryo, from an oviraptorid (a type of theropod dinosaur ), is curled up in a posture strikingly similar to modern bird embryos just before they hatch. This “tucking” position helps birds hatch successfully, and the fossil suggests that dinosaurs were doing something very similar millions of years before birds evolved.

Fossil embryos are incredibly rare, and this one shows behavior, not just bones. The positioning of the embryo hints at coordinated movements before hatching , revealing that certain survival strategies we associate with birds actually originated in dinosaurs.

This discovery strengthens the evolutionary link between non-avian dinosaurs and birds, showing how behaviors can be inherited across millions of years . It’s another powerful piece of evidence that evolution isn’t just about anatomy, it’s about behavior, development, and adaptation over time.

Reference:
Xing, L., Persons, W. S., O’Connor, P., Wang, Y., Tan, Q., Wang, M., … & Zhou, Z. (2021). An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures. iScience, 24(11), 103394. https://doi.org/10.1016/j.isci.2021.103394