A team of US scientists has demonstrated that the offspring of huge carnivorous dinosaurs like Tyrannosaurus rex, who grew from the size of house cats to towering monsters, reshaped their ecosystems by outcompeting smaller rival species.

What's more, across the entirety of the Mesozoic era, from 252 to 66 million years ago, there were relatively many more species of large bodied dinosaurs weighing 1,000 kilograms (a ton) compared to species weighing less than 60 kilograms (130 pounds).

To test the theory, Schroeder and her colleagues examined data from fossil sites around the world, including over 550 dinosaur species, and organized the dinosaurs by whether they were herbivores or carnivores, as well as their sizes.

"Very few carnivorous dinosaurs between 100-1,000 kilograms (200 pounds to one ton) exist in communities that have megatheropods," Schroeder said.