There is one remaining mystery, though. All of the dwarf dinosaurs found to date are still, fundamentally, pretty large animals. Europasaurus and Magyarosaurus managed to shrink, but each only reached the size of a cow..
It wasn't just the dwarf dinosaurs that were relatively large. Earlier this year Benson and his colleagues looked at animal body size throughout the dinosaur age. In 170 million years, only one group of dinosaurs managed to evolve bodies less than 1 kilogram in weight: the group of dinosaurs that includes birds.
“More than 80% of living mammals weigh less than 1 kilogram,” says Benson. “Almost zero dinosaurs other