Dinosaurs might have ruled the planet out of sheer luck. The dominant status that dinosaurs enjoyed for some 135 million years had suggested there was something inherently superior about the creatures. To see why the dinosaurs rose to prominence, paleontologists investigated the first years of their existence in the late Triassic, from 230 million to 200 million years ago. The researchers discovered their main competitors at that time, the crurotarsans (ancestors to crocodiles), thrived—the fossil record shows that crurotarsans were actually twice as diverse as dinosaurs when it came to body types, diets and ways of life and that they were more abundant in many ecosystems. Hence, the scientists, from the University of Bristol in England and the American Museum of Natural History in New York City, conclude that dinosaurs did not outcompete crurotarsans, which were largely wiped out by rapid climate change at the end of the Triassic. For some reason, the change did not affect the dinosaurs; the crurotarsans might have easily inherited the earth instead. Dig up more in the September 12 Science.