Dinosaurs might have gone extinct because their eggs took so long to hatch, new findings suggest

Eggs took as much as six months to incubate, the groundbreaking new research claims

Researchers examined a fossilised embryo of the dinosaur hypacrosaurus (DARLA ZELINITSKY)

Dinosaurs might have gone extinct partly because they took so long to be born.

New research suggests that dinosaur eggs took as much as six months to hatch – far longer than the process takes in birds, which scientists had previously compared them to. And that lengthy period might have endangered the animals to the point that it contributed towards their extinction.

The amount of time taken for an animal to incubate varies wildly, and doesn't necessarily say anything about the animal. While a human baby usually takes nine months before it is ready to be born, ostriches spend 42 days in their eggs.

Scientists had long presumed that dinosaurs followed birds in their incubation. Their eggs take between 11 and 85 days, usually, and scientists presumed that they inherited that quick incubation from their dinosaur ancestors.

But in fact that process could take three to six months, according to the new research. It looked at a tooth found in an egg laid by a non-avian dinosaur, and traced the markers of ageing that could be found in it.

That long incubation process might have contributed towards the dinosaurs dying out. The traditional explanation of a rock crashing into Earth and wiping them out still holds – but the new research suggests that the eggs taking so long might have slowed down the repopulation after that fact, holding the dinosaurs back from replacing those animals that were wiped out during the catastrophic event.

Not only did the animals take a long time to hatch, they would also have taken a long time to become mature. Taken together, that might mean that the dinosaurs took almost two years to become fully grown from being conceived – far too long in the harsh environment after the comet or asteroid hit.

Scientists say that the same findings could help inform our understanding of what the dinosaurs were doing when they were alive, however. They probably migrated less than we had previously thought given how hard it would be to do that while having young, for instance.