Kenya
The reserve is 1,510 km2 (583 sq mi), primarily, open grassland and lies beside the Serengeti National Park in Mara Region, Tanzania. The first of the sanctuary was established in 1961. It is a major research center for the spotted hyena, and host to an exceptional population of lions, leopards and cheetahs, and the annual migration of zebra, Thomson's gazelle, and wildebeest.