The large size of hadrosaurid eyes and the presence of sclerotic rings in the eyes imply acute vision and diurnal habits, evidence that sight was important to these animals. The hadrosaurid sense of hearing also appears to be strong. There is at least one example, in the related "Corythosaurus", of a slender stapes in place, which combined with a large space for an eardrum implies a sensitive middle ear. The auditory part of the inner ear was well-developed. If used as a noisemaker, the crest could also have provided recognizable differences for different species or sexes, because the differing layouts of the nasal passages corresponding to the different crest shapes would have produced different sounds.