Why did mammals manage to survive the apocalyptic event that killed off the dinosaurs, while the terrible lizards disappeared from the face of the earth? Thanks to a mathematical model, a group of researchers think they've figured out the culprit: Eggs. Because dinosaurs laid eggs, their young were born weighing as little as 4 to 22 pounds, compared to their eventual size of more than 30 tons, the Telegraph explains.
Why was that a problem? Because it meant there were no small dinosaur species; the space a smaller dinosaur species would have occupied in the ecosystem was taken up by young large dinosaurs. So when an event wiped out the large dinosaurs, there were no smaller species to take their place. Mammals, whose young were not as comparatively small and weren't competing with other species for food, didn't have that problem. On the plus side for dinosaurs, at least their deadly eggs are going to make a great tourist attraction in Chechnya. (Read more mammals stories.)