Eggs are not a great way to reproduce, unless you want to reproduce with the Bacons. You have to lay them somewhere they won’t get crushed or eaten, some species are compelled to protect them, and they’re difficult to move. All that wasn’t great news for the dinosaurs when that asteroid hit, but a new study reveals an even bigger problem: Dinosaurs took forever to hatch.
To this point, scientists have assumed dinos were like their genetics descendants, birds. Birds lay a small amount of large eggs that gestate quickly; a chicken, for example, is out of its shell in three weeks. Dinosaurs were just assumed to be the same way. But it turns out, examination of signs of growth of two dinosaur embryos showed a gestation period of three to six months, possibly even longer.
Taking months to be born is fine when your habitat is consistent and volcanoes aren’t exploding everywhere, but months-long gestation would mean dinosaurs began losing more eggs thanks to constant environmental change, and that they couldn’t renew their populations quickly enough to keep up with the various disasters that were quickly wiping them out. It would also line up with the behavior of birds: After all, the species that did manage to hatch quickly would have an evolutionary advantage. It’s not clear that this is consistent across all dinosaur species, but if it is, we’ve found yet another reason that the dinosaurs were up the creek once that asteroid hit.