Horn of Africa periodic monsoon winds and irregular rainfall. Mean daily maximum temperatures range from , except at higher elevations along the eastern seaboard, where the effects of a cold offshore current can be felt. Somalia has only two permanent rivers, the Jubba and the Shabele, both of which begin in the Ethiopian Highlands. About 220 mammals are found in the Horn of Africa. Among threatened species of the region, there are several antelopes such as the beira, the dibatag, the silver dikdik and the Speke's gazelle. Other remarkable species include the Somali wild ass, the desert warthog, the hamadryas baboon, the Somali
Languages of Africa expansion, in which Bantu-speaking peoples expanded over most of Sub-Equatorial Africa, displacing Khoi-San speaking peoples from much of Southeast Africa and Southern Africa and other peoples from Central Africa. Another example is the Arab expansion in the 7th century, which led to the extension of Arabic from its homeland in Asia, into much of North Africa and the Horn of Africa. Trade languages are another age-old phenomenon in the African linguistic landscape. Cultural and linguistic innovations spread along trade routes and languages of peoples dominant in trade developed into languages of wider communication (lingua franca). Of particular importance in this