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.
The majority of their food is found on the floor of the rainforest where it has fallen from trees above. They also eat fruit from branches they can reach. They occasionally consume small vertebrates, fungi, and insects. One study discovered that the cassowary is an important disperser of many species of rainforest plants. It was found that many of the seeds and fruits the cassowary ate passed nearly intact through the digestive tract of the bird.