Dino Day Care

A Massospondylus parent cares for its young in an artist's rendering. 

The newfound dinosaur-egg clutches provide the oldest evidence yet for several aspects of dinosaur behavior, according to the study.

For example, paleontologists found multiple nests in a single layer of rock, suggesting that mothers gathered in groups to lay their eggs. This is the oldest example of "colonial nesting" in the fossil record, the scientists say.