It is one of the largest birds in the world. They have a large size and strong legs that allow them to run. These are running, non-flying birds. Cassowaries have three thick fingers, of which the inner one is smaller and in which there is a sharp claw that can reach 12 centimeters in length.

Its body is covered in fine black feathers that look similar to thick hair. This dense plumage protects it from the thorns present in the vegetation. The neck and head are devoid of feathers, and it stands out for having a bright blue and red color. On their heads they also have a bony and cartilaginous helmet that allows them to break tree branches when they run through the jungle, thus protecting their head from the blows that the branches would cause.

The wings are extremely small, as they are not needed for flight, and a vestige of primary feathers remains that resemble 5 or 6 long black white spines.
At birth, cassowary chicks are brown with black stripes along their body. These stripes disappear at six months of age. Juveniles are brown and have a small helmet. They do not acquire the bright color of the neck until they are approximately one year old.

They are solitary animals, except during the breeding season. The female lays 2 or 3 eggs of 3 to 5 eggs in a nest prepared by the male. Once laying is complete, the female leaves the nest and goes in search of a new male with whom to mate and lay more eggs. It is the males who incubate the eggs and take care of the little ones until they are 9 months old.