A population of approximately 25,000 large animals, largely ungulates along with reputedly the highest density of mammalian predators in Africa, lives in the crater. Large animals in the crater include the black rhinoceros, the local population of which declined from about 108 in 1964-66 to between 11-14 in 1995, and the hippopotamus, which is very uncommon in the area. There also are many other ungulates: the wildebeest (7,000 estimated in 1994), the zebra (4,000), the eland, and Grant's and Thompson's gazelles (3,000).
Female lions on the hunt in Ngorongoro Crater
The crater has the densest known population of lions, numbering 62 in 2001. On the crater rim are leopards, elephants - numbering 42 in 1987 but only 29 in 1992 - mountain reedbuck, and buffalo (4,000 in 1994).
However, since the 1980s the crater's wildebeest population has fallen by a quarter to about 19,000 and the numbers of eland and Thomson's gazelle also have declined while the buffalo population has increased greatly, probably due to the long prevention of fire which favors high-fibrous grasses over shorter, less fibrous types.
In summer, enormous numbers of Serengeti migrants pass through the plains of the reserve, including 1.7 million wildebeest, 260,000 zebra, and 470,000 gazelles. Waterbuck occur mainly near Lerai Forest; servals occur widely in the crater and on the plains to the west. Common in the reserve are lions, hartebeest, spotted hyenas and jackals. Cheetahs, although common in the reserve, are scarce in the crater itself. The African Wild Dog has recently disappeared from the crater and may have declined elsewhere in the Conservation Area as well, as well as throughout Tanzania according to C. Michael Hogan.