Crocodile float on water stream

Many crocodiles vocalize to communicate. The young of various species use several squeaking and grunting sounds, and adults may grunt, growl, and hiss. For example, Siamese crocodiles and caimans emit a loud hiss when threatened, and hatchlings of most species make sounds described as grunts or quacks. In addition, members of both sexes may produce a loud roar during the breeding season. A roaring crocodile tenses the muscles of its body so that the head and tail rise high out of the water. The flanks may vibrate so violently that water is sprayed high into the air from each side. Sounds, including roars, may be provoked by any loud noise. Many species will respond to gunshots, motors, and even people mimicking crocodile sounds. These animals also appear to communicate using chemical signals. Glands in the mandible and cloaca excrete oily chemicals that have a poorly understood function in communication.