I t was long thought the Ice Age killed off the dinosaurs, but maybe it was something less dramatic: slow gestation.
New research from a team at Florida State University (FSU) and the University of Calgary (UC) suggests that baby dinosaurs took between three and six months, depending on their size, to hatch. Unlike birds and other small mammals, which take only a few weeks to develop, the long gestation period of dinosaurs could be crucial to understanding what made them vulnerable to other predators and environmental risks.
Gregory Erickson, professor of Biological Science at FSU, argues that nothing was known about dinosaur embryology until this research, which used two rare embryos millions of years old. One belonged to a Protoceratops, a sheep-sized dinosaur found in the Gobi desert whose eggs were relatively small, the other two a Hypacrosaurus, a 30-foot duck-billed dinosaur found in Alberta, Canada.
According to Professor Erickson, dinosaur teeth are “a bit like tree rings”. However, instead of being an annual record, these "signifiers are put down daily”. As a result he and his team “could literally count them to see how long each dinosaur had been developing". From this they were able to determine that a Protoceratops took three months, and Hypacrosaurus six, to gestate.
The study concludes that this long gestation period, coupled with the year that it took for a dinosaur to reach maturity, and the considerable resources needed to reach adult size, would have been a distinct disadvantage. In the harsh conditions of the Cretaceous age it is possible that dinosaurs simply took too long to reproduce.