No one really knows if dinosaurs had voices. Maybe some did and others didn't. Hadrosaurs had a hollow in their head crest, and they may have trumpeted sounds through it almost the way an elephant uses its trunk. Sound leaves no visible record and so the question of whether dinosaurs could communicate may be the most difficult question of all. However, there is fossil evidence to show that the nostrils of Hadrosaurs were elongated. The hollow in the head crest might have acted as a kind of echo chamber; a noise formed in the throat trumpeted through the crest for identification of species, communication, mating and warnings. Parasaurolophus, or the archetypal Hadrosaaurus, was named the trombone duckbill because of its facial structure.