Around 65 million years ago, all land-based dinosaurs were wiped off the face of the Earth. But, while these dinosaurs floundered, many mammal species survived, going on to thrive in a dinosaur-free world.
How come? Well, researchers at the University of Zurich in Switzerland and the Zoological Society of London have come up with an egg-citing idea. Unlike mammals, which mostly give birth to live young, dinosaurs laid eggs. This meant that baby dinosaurs were tiny compared to their final adult size, growing from a few kilograms to as much as 30 or 50 tonnes.
Because dinosaurs started off so small, they had to compete for food with many differently sized species as they grew up. In other words, the babies of large adult dinosaurs were pitted against the smaller adult dinosaurs. This pushed adult dinosaurs to grow larger and larger in order to gain a competitive edge over the younger upstarts.
And, because it was the larger animals that suffered 65 million years ago (they required more food to survive, which was in increasingly short supply), the land-based dinosaurs were obliterated, allowing the smaller mammals to go forth and multiply.
Whilst there’s probably not much chance of resurrecting these lost dinosaurs any time soon, there has been a lot of talk about bringing a certain prehistoric mammal back to life. In this month’s Focus, on sale now, read about the possibility of cloning the woolly mammoth.