This natural event is famous for involving a great population of large mammals. Huge numbers of herbivores migrate each year, followed by the big cats. The zebra, Thomson's gazelle, wildebeest, African buffalo, giraffe, elephants and others arrive to eat fresh grass after the rain, and later move on. Lions, leopards, cheetahs follow, and also vultures and hyaenas. hippos and Nile crocodiles are in the rivers. It is called "The Great Migration".