The Serengeti Park and the Ngorongoro Conservation Area provide a river and lake environment that is ideal for wildebeest, of which there are many. Their numbers are estimated at around one million six hundred thousand, who take refuge in Kenya during the dry season. They return with the rains, and long processions of animals can be seen in search of fresh grass. This annual migration is the park's most striking natural phenomenon.
This migration means that the animals can be seen in different parts of the park depending on the season: in the north from July to October, in the south from December to March, and in the center (Seronera) at intermediate periods.
In addition to the wildebeest, which dominate in terms of numbers, the park is also home to the five species that make up the Big Five (the name given to this group of species by African safari hunters in the 20th century): lion, leopard, elephant, rhinoceros (in small numbers) and African buffalo (Syncerus caffer). The park is also home to hyenas, cheetahs, zebras, giraffes, birds of prey and many other species. This profusion of animals has generated a local economy revolving around what is sometimes called ecotourism, and Tanzania is now very careful to exploit this local wealth rationally, both through protection policies and specific taxation of tourist activities.
Near the park is Olduvai Gorge, where numerous fossils and human remains have been unearthed. The park is also adjacent to the Ngorongoro Conservation Area, and is part of the greater Serengeti ecosystem. It is listed by UNESCO as a World Heritage Site. The administrative body for all Tanzania's parks is Tanzania National Parks (TANAPA).