Their main food is fruit, but they eat other things such as snails, fungi, ferns and flowers. They are important because they spread plant and fruit seeds through the forest. Each cassowary is known to live in an area of up to , so they carry seeds a long way. At least 70 rainforest trees need the cassowary to spread their seeds. Their seeds are too big for other rainforest animals to carry. Seeds from 21 plants have to be eaten and pass through the cassowary or they will not grow. Some seeds are poisonous to all other animals; only the cassowary can eat them. Scientists have worked out that about 150 rainforest plants need the cassowary.