Parasaurolophus
Late Cretaceous dinosaur (about 75 million years ago), Parasaurolophus could measure up to 32 feet tall and weigh more than 2 tons! This large, flat-billed herbivore is known for its long bony crest surmounting its head. This impressive ridge could be up to 6 feet long and probably had several functions. Hollow and connected to the nose, it seems that it allows the Parasaurolophus to emit sounds and thus communicate with its congeners.