The Ngorongoro Crater is a natural amphitheatre created about 2 million years ago when the cone of a volcano collapsed into itself, leaving a 160 square kilometres caldron-like cavity. This caldera, protected by a circular unbroken 610 metres high rim, contains everything necessary for Africa's wildlife to exist and thrive.
Ngorongoro is on Tanzania's northern safari circuit, and receives a good number of visitors who stay in lodges around the crater. Game viewing vehicles descend the steep crater wall every morning and spend the day on grass plains that are teeming with animals. However, the dark of night belongs to the animals, and all vehicles must leave the crater floor by sunset.
Early man also flourished around here at Olduvai Gorge, not far from the Ngorongoro Crater. This is known because in 1960, Mary Leakey discovered a 1.75 million-year-old Homo habilis (nicknamed 'The Handyman' for his tool making skills), who represents mans first step on the ladder of human evolution.
The Maasai are the current human inhabitants and are at liberty to live within the sprawling 6,480 sq kilometres conservation area around the crater. The Maasai never cultivate land as they consider it demeaning. Instead they graze cattle, which hold a god-like status in Maasai culture, and in return the cows provide almost everything necessary to live.

Animals and Birds
The 'lost world' of Ngorongoro was home to pigs the size of a hippopotamus, sheep-like beasts with 3 metre horns and three-toed horses. Nowadays is inhabited by about 30,000 animals, of which half are zebra and wildebeest. This is the perfect situation for predators, spotted hyenas and lions lord over this domain. There are also some leopards, cheetahs and three species of jackals. Tanzania's few remaining black rhino are regularly sighted in the crater, as are large herds of buffalo.
In the lake on the crater floor and in the Ngoitokitok swamps, reside plenty of hippos who remain partially submerged during the day and graze on grass at night.
Although the area sustains a huge variety of species, not all live down in the crater. Some are better adapted to roaming the extensive conservation area surrounding the caldera.
Elephant herds are noticeably absent from the crater floor because the cows and calves tend to prefer the forested highlands. They sometimes appear at the crater rim but only rarely venture down into the grasslands. Only mature bull elephants roam the crater floor carrying around some massive tusks. Also absent from the crater are impala, topi and oryx who reside more on the eastern Serengeti plains, but Grant's and Thompson's gazelles appear in the crater in good numbers. Giraffes are also missing from the crater as they favour the umbrella acacia and wait-a-bit thorn trees found higher up.
The salt-whitened shores of Lake Magadi are turned a pastel pink from thousands of flamingoes sifting algae and shrimps from this soda lake. The lake also attracts a myriad other water birds including avocets, plovers and black-winged stilts whose long beaks probe the soft mud.

Seasons
As the rim of the crater is 2,235 m above sea level it is cooler at the top than down on the crater floor, where it can get extremely hot.Short rains are November and December when it gets hot and humid, and the long rains are from March to May.Typically it is dry from June to October and it can get quite cold during these months on the rim of the crater.