How long would it take for a dinosaur egg to hatch? A study , led in part by Dr. Gregory Erickson at Florida State University , counted how long it took dinosaur "baby teeth" to develop in the egg to find out. The study, published in the journal PNAS, looked at two dinosaur species: Protoceratops andrewsi and Huypacrosarus stebingeri , studying how quickly the teeth developed in the egg, and how long those teeth would need to develop before the baby dino was ready to hatch. Dr. Ericskon explains