Nowhere in the world is there a movement of animals as immense as the wildebeest migration. Over two million animals migrate from the Serengeti National Park in Tanzania to the greener pastures of the Masai Mara National Reserve in Kenya during the period of July - October.
Due to long dry spells in the months of April and May, the movement may start a little early in a particular year for there may not be enough water to support the growth of grass, and thus, the wildebeests (gnus).
Over the years, when the wildebeests arrive early, they often go back again into Serengeti after a while. However, they come back again later in the months of September-October, before making a final return. The herds have to cross the Mara River in Masai Mara where crocodiles feast on them. This is one of the anxious times for the animals as they try to make to the other side of the river alive. But this is one of many amazing natural phenomenon that we witness on and around this planet earth.