This long period of development may have been what doomed them, Erickson said. After an asteroid crashed into the earth 66 million years ago, triggering a mass extinction, it would have been harder for slowpoke reproducers like dinosaurs to recover.
"Dinosaurs Took Months to Hatch Out of Their Eggs. That May Have Doomed Them." is from the January 03, 2017 Speaking of Science section of The Washington Post. It was written by Sarah Kaplan and narrated by Sam Scholl.