Pictured above is the black rhinoceros. There are five different species of the rhino and they are actually part of the horse family. They have thick skin and a horn in the middle of the head (the black rhino has two horns). They are herbivores, live in grasslands or woodlands, and can become agressive if they feel threatened or provoked. Humans are a predator because they have hunted the rhino for its horns. However, trading rhinoceros horn is illegal all over the world because they are endangered. There are only 2,500 rhinos left, when 100 years ago there were almost a million of them in Africa.