The bionic dinosaurs are here. Six of them roar and swish their tails in a dimly lit hall at the Carnegie Museum of Natural History in Pittsburgh. There’s a stegosaurus, triceratops, tyrannosaurus rex, corythosaurus and an adult and baby apatosaurus. The beasties are run by compressed air; to create their roar, museum curators researched the sounds made by crocodilians. Dinosaurs Alive! remains in Pittsburgh through Sept. 25, then travels.