Ngorongoro Conservation Area

At last we arrived at the Ngorongoro Conservation Area with its vast crater and hopes of seeing the big 5: Lions, Rhinos, Buffalo, Elephants, and Leopards.

The main feature of the NCA is the Ngorongoro Crater, a large, unbroken, unflooded volcanic caldera. The crater, which formed when a giant volcano exploded and collapsed on itself some two to three million years ago, is 610 m (2,000 ft) deep and its floor covers 260 km2 (100 sq mi). Estimates of the height of the original volcano range from fifteen to nineteen thousand feet (4500 to 5800 metres) high.

Although thought of as "a natural enclosure" for a very wide variety of wildlife, up to 20% or more of the wildebeest (Connochaetes taurinus) and half the zebra (Equus burchelli) populations vacate the Crater in the wet season. However, a side effect of this enclosure is that the population of Ngorongoro lions is significantly inbred, with many genetic problems passed from generation to generation. This is due to the very small amount of new bloodlines that enter the local gene pool, as very few migrating male lions enter the crater from the outside. Those who do enter the crater are often prevented from contributing to the gene pool by the crater's male lions, who, because of their large size (the result of an abundant and constant food source), easily expel any outside competitors. Animal populations in the crater include most of the species found in East Africa, but there are no impalas (Aepyceros melampus), topis (Damaliscus lunatus), oribis (Ourebia oribi), giraffes (Giraffa camelopardalis), or crocodiles (Crocodylus niloticus).

The crater highlands on the side facing the easterly trade winds receives 800–1200 mm of rain a year and is covered largely in montane forest, while the less-steep west wall receives only 400–600 mm; this side is grassland and bushland dotted with Euphorbia bussei trees. The crater floor is mostly open grassland with two small wooded areas dominated by Acacia xanthophloea.

The Munge Stream drains Olmoti Crater to the north, and is the main water source draining into the seasonal salt lake in the center of the crater. This lake is known by two names: Makat as the Maasai called it, meaning salt; and Magadi.The Lerai Stream drains the humid forests to the south of the Crater, and it feeds the Lerai Forest on the crater floor - when there is enough rain, the Lerai drains into Lake Magadi as well. Extraction of water by lodges and NCA headquarters reduces the amount of water entering Lerai by around 25%.

The other major water source in the crater is the Ngoitokitok Spring, near the eastern crater wall. There is a picnic site here open to tourists and a huge swamp fed by the spring, and the area is inhabited by hippopotamus, elephants, lions, and many others. Many other small springs can be found around the crater's floor, and these are important water supplies for the animals and local Masaai, especially during times of drought.

Aside from herds of zebra, gazelle, and wildebeest, the crater is home to the "big five" of rhinoceros, lion, leopard, elephant, and buffalo. The crater plays host to almost every individual species of wildlife in East Africa, with an estimated 25 000 animals within the crater.