Sub-Saharan Africa is, geographically, the area of the continent of Africa that lies south of the Sahara Desert. Politically, it consists of all African countries that are fully or partially located south of the Sahara (excluding Sudan, even though Sudan sits in the Eastern portion of the Sahara desert).〔(【引用サイトリンク】title=Political definition of "Major regions", according to the UN. )〕 It contrasts with North Africa, which is considered a part of the Arab world. Somalia, Djibouti, Comoros, and Mauritania are geographically part of Sub-Saharan Africa, but also part of the Arab world.〔Halim Barakat, ''The Arab World: Society, Culture, and State'', (University of California Press: 1993), p.(80 )(Arab League Online: League of Arab States )
(【引用サイトリンク】title=UNESCO - Arab States )
Khair El-Din Haseeb et al., ''The Future of the Arab Nation: Challenges and Options'', 1 edition (Routledge: 1991), p.54
John Markakis, ''Resource conflict in the Horn of Africa'', (Sage: 1998), p.39
Ḥagai Erlikh, The struggle over Eritrea, 1962-1978: war and revolution in the Horn of Africa, (Hoover Institution Press: 1983), p.59
Randall Fegley, ''Eritrea'', (Clio Press: 1995), p.xxxviii
Michael Frishkopf, ''Music and Media in the Arab World'', (American University in Cairo Press: 2010), p.(61 )〕
The Sahel is the transitional zone between the Sahara and the tropical savanna (the Sudan region) and forest-savanna mosaic to the south.
Since probably 3500 B.C.E,〔("Sahara's Abrupt Desertification Started by Changes in Earth's Orbit, Accelerated by Atmospheric and Vegetation Feedbacks" ), Science Daily.〕〔
〕 the Saharan and Sub-Saharan regions of Africa have been separated by the extremely harsh climate of the sparsely populated Sahara, forming an effective barrier interrupted by only the Nile River in Sudan, though the Nile was blocked by the river's cataracts. The Sahara pump theory explains how flora and fauna (including ''Homo sapiens'') left after to penetrate the west and beyond. African pluvial periods are associated with a "wet Sahara" phase during which larger lakes and more rivers existed.
==Etymology==
Geographers historically divided the region into several distinct ethnographic sections based on each area's respective inhabitants.
Commentators in Arabic in the medieval period used the general term ''bilâd as-sûdân'' ("Land of the Blacks") for the vast Sudan region (an expression denoting West and Central Africa), or sometimes extending from the coast of West Africa to Western Sudan.〔Nehemia Levtzion, Randall Lee Pouwels, The History of Islam in Africa, (Ohio University Press, 2000), p.255.〕 Its equivalent in Southeast Africa was ''Zanj'' ("Country of the Blacks"), which was situated in the vicinity of the Great Lakes region.〔〔
The geographers drew an explicit ethnographic distinction between the Sudan region and its analogue Zanj, from the area to their extreme east on the Red Sea coast in the Horn of Africa.〔 In modern-day Ethiopia was ''Al-Habash'' or Abyssinia,〔Sven Rubenson, The survival of Ethiopian independence, (Tsehai, 2003), p.30.〕 which was inhabited by the ''Habash'' or Abyssinians, who were the forebears of the Habesha.〔Jonah Blank, Mullahs on the mainframe: Islam and modernity among the Daudi Bohras, (University of Chicago Press, 2001), p.163.〕 In northern Somalia was ''Barbara'' or the ''Bilad al-Barbar'' ("Land of the Berbers"), which was inhabited by the Eastern ''Baribah'' or ''Barbaroi'', as the ancestors of the Somalis were referred to by medieval Arab and ancient Greek geographers, respectively.〔〔F.R.C. Bagley et al., ''The Last Great Muslim Empires'', (Brill: 1997), p.174〕〔Bethwell A. Ogot, ''Zamani: A Survey of East African History'', (East African Publishing House: 1974), p.104〕〔James Hastings, ''Encyclopedia of Religion and Ethics Part 12: V. 12'', (Kessinger Publishing, LLC: 2003), p.490〕