Pterosaurs and their eggs
Pterosaur eggs had a soft, porous, and leathery shell, and are rare in the fossil record. A handful of extraordinary finds reveal how pterosaurs nested, laid, and cared for their young.
Communal nesting ground
120 million years ago, large numbers of Hamipterus would annually gather on an isolated lakeside beach in what is now western China. Through the centuries, this nesting ground met with disaster: on at least eight different occasions, flood waters swept through the site, killing large numbers of adults and washing the eggs into the lake. Many birds nest on isolated beaches to avoid predators, and beach-nesting pterosaurs like Hamipterus may have had the same motivations.
Hundreds of Hamipterus eggs have been discovered with the adults, washed into the middle of the lake by storms. Most pterosaur babies and embryos show they could fly at a very young age, but Hamipterus may have been different: their bones and joints were less developed than other baby pterosaurs, and they may have spent a long time in the nest after hatching, like many birds.
A mother and her egg
This 160-million-year-old Darwinopterus fossil from China shows a female and her egg. This find and others show that pterosaur females commonly had wider hips, and lacked head crests or had a smaller one compared to males.
Pterosaur eggs had a soft, porous, and leathery shell. Today, such eggs are commonly buried under soil or piles of vegetation to keep them from drying out. Pterosaur parents might have done the same with their eggs.
