The new "Jurassic World" movie trailer features growling, grunting and shrieking dinosaurs. These bellows may make for good entertainment at theaters, but do paleontologists actually know how dinosaurs sounded?
"It is not easy to study dinosaur sounds," said Lindsey Zanno, an assistant research professor of paleontology at North Carolina State University. "Vertebrates usually vocalize with soft tissues, and soft tissues rarely preserve in the fossil record." (Human vocal cords are made of soft tissue.)