One of the cassowary's most distinguishing features is the large protuberance on the top of its head called the casque. It is believed that the casque assists the cassowary in pushing through the dense tropical forest vegetation, and may also provide some sort of protection. In captivity, cassowaries have been observed using their casques like a shovel to search for food on the ground. It is believed that the size of the casque may indicate dominance and age, since the casque continues to grow throughout the life of the bird. Another distinguishing feature of the cassowaries is their wattles.
Wattles are present in two of the three species of cassowary.
These brilliantly colored folds of skin hang from the bird's neck, and may act as social signals in the dark forest. Their feet are equipped with sharp claws and the inner toe is formed into a long dagger-like claw that can be a formidable weapon. They are most often found in the rain forest, occasionally straying to swampy forested areas. They are excellent swimmers and are often found along river banks. Cassowaries are frugivorous birds.