Mix the sounds of different animals to create the roar of the Tyrannosaurus rex!

In movies, T. rex always has a ferocious roar. Did it in real life too? No one knows for sure. But scientists can study the closest living relatives of  T. rex , crocodiles and birds, for clues. And a giant animal like T. rex would have made lower-pitched sounds than smaller animals. So scientists study large living animals for clues too!