Some species have been observed to hunt cooperatively. Even when large numbers congregate, they do not seem to fight over food. When large prey is caught, another crocodile may help to dismember it, so that the peices are small enough to eat. Crocodilians communicate with each other by means of sounds, postures, motions, odors released by four scent glands, and by touch. Young call to adults when in danger, but also are very vocal while being fed.
Adults also produce sounds to communicate with other adults.
The most common adult sound is a loud, low roar which is repeated, and may be echoed by other adults. Threatened crocodilians may growl. Adults also grunt to signal to juveniles they will help, and may hiss while defending juveniles. They also communicate by slowly lifting their jaws off the ground with their mouth closed. Adults are territorial, and mark their territory by loudly slapping their head down on the water or snapping their jaws on the surface of the water.