Many suggestions have been made for the function or functions of the crest , including housing salt glands , improving the sense of smell , use as a snorkel or air trap , acting as a resonating chamber for making sounds , or being a method for different species or different sexes of the same species to recognize each other .
They include housing salt glands , improving the sense of smell , use as a snorkel or air trap , acting as a resonating chamber for making sounds , or being a method for different species or different sexes of the same species to recognize each other .