Great Karoo

Karoo
Natural region
Typical Karoo vegetation to the south of Matjiesfontein, with the Anysberg Mountains visible in the background
Extent of the Karoo (olive-green) and Little Karoo (bright green) in South Africa, with the names of surrounding areas in blue. The thick interrupted line indicates the course of the Great Escarpment which delimits the Central South African Plateau. To the immediate south and south-west the solid lines trace the parallel ranges of the Cape Fold Belt.
Country	South Africa

The Karoo (/kəˈruː/ kə-ROO; from a Khoikhoi word, possibly garo "desert") is a semi-desert natural region of South Africa. There is no exact definition of what constitutes the Karoo, and therefore its extent is also not precisely defined. The Karoo is partly defined by its topography, geology, and climate — above all, its low rainfall, arid air, cloudless skies, and extremes of heat and cold. The Karoo also hosted a well-preserved ecosystem hundreds of million years ago which is now represented by many fossils.

The Karoo formed an almost impenetrable barrier to the interior from Cape Town, and the early adventurers, explorers, hunters and travelers on the way to the Highveld unanimously denounced it as a frightening place of great heat, great frosts, great floods and great droughts. Today it is still a place of great heat and frosts, and an annual rainfall of between 50–250 mm, though on some of the mountains it can be 250–500 mm higher than on the plains. However, underground water is found throughout the Karoo, which can be tapped by boreholes, making permanent settlements and sheep farming possible.

The xerophytic vegetation consists of aloes, mesembryanthemums, crassulas, euphorbias, stapelias, and desert ephemerals, spaced 50 cm or more apart, and becoming very sparse going northwards into Bushmanland and, from there, into the Kalahari Desert. The driest region of the Karoo, however, is its southwestern corner, between the Great Escarpment and the Cederberg-Skurweberg mountain ranges, called the Tankwa Karoo, which receives only 75 mm of rain annually. The eastern and north-eastern Karoo are often covered by large patches of grassland. The typical Karoo vegetation used to support large game, sometimes in vast herds.