( , , "The Greatest Desert") is the
world's largest hot desert
over9,000,000 square kilometres (3,500,000
sq mi), it covers most of Northern Africa, making it almost as large
as the United
States or the continent of Europe. The desert stretches from the Red Sea, including
parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean.
To the south, it is delimited by the
: a belt of semi-arid
that comprises the northern region of central
and western Sub-Saharan
The Sahara has an intermittent history that may go back as much as
3 million years. Some of the sand dunes can reach 180 metres
(600 ft) in height.The name comes from the Arabic word for
desert: (صَحراء), "ṣaḥrā´" ( ; ).
Sahara's boundaries are the Atlantic Ocean on the west, the Atlas
Mountains and the Mediterranean Sea on the north, the Red Sea and Egypt on the east,
and the Sudan and the valley of the
Niger River on the south.
is divided into western Sahara, the central Ahaggar
Mountains (a region of desert mountains and high plateaus),
Ténéré desert and the Libyan desert (the most arid region). The highest peak in
the Sahara is Emi
Koussi ( ) in the Tibesti Mountains in northern Chad.
The Sahara divides the continent
and Sub-Saharan Africa
southern border of the Sahara is marked by a band of semiarid
savanna called the Sahel; south of the Sahel lies the lusher Sudan and
the Congo River
Most of the Sahara consists of rocky
(large sand dunes
) form only a minor
People lived on the edge of the desert thousands of years ago since
the last ice age
. The Sahara was then a much
wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in the
n'Ajjer in southeast Algeria.
, have also been found here.
The modern Sahara, though, is not lush in vegetation, except in the
Valley, at a few oases
, and in the northern highlands, where
Mediterranean plants such as the olive
are found to grow. The region has been this way since about 5000
years ago. Some 2.5 million people currently live in the
Sahara, most of these in Egypt, Mauritania, Morocco and Algeria.
ethnicities in the Sahara are various Berber groups including Tuareg tribes, various Arabised
Berber groups such as the Hassaniya-speaking Maure (Moors, also known as Sahrawis), and various black African ethnicities
including Tubu, Nubians, Zaghawa, Kanuri, Peul (Fulani),
Hausa and Songhai. Important cities located in the Sahara
include Nouakchott, the capital of Mauritania; Tamanrasset, Ouargla, Bechar, Hassi
Messaoud, Ghardaia, El
Oued, Algeria; Timbuktu, Mali; Agadez, Niger; Ghat, Libya; and
Sahara covers huge parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western
Sahara, Sudan and Tunisia.
A geographical map of Africa, showing
the ecological break that defines the Saharan area
It is one of three distinct physiographic
provinces of the
African massive physiographic division
The desert landforms of the Sahara are shaped by wind (eolian
) or by occasional rains, and include sand
dunes and dune fields or sand seas (erg
), stone plateaus (hamada)
, gravel plains (reg)
, and salt flats (shatt
landforms include the Richat Structure in Mauritania.
deeply dissected mountains and mountain ranges, many volcanic, rise
from the desert, including the Aïr Mountains, Ahaggar Mountains, Saharan
Atlas, Tibesti Mountains, Adrar des Iforas,
and the Red Sea
hills. The highest peak in the Sahara is Emi Koussi, a shield volcano in
the Tibesti range of northern Chad.
Most of the rivers and streams in the Sahara are seasonal or
intermittent, the chief exception being the Nile River
, which crosses the desert from its
origins in central Africa to empty into the Mediterranean.
sometimes reach the surface, forming oases,
including the Bahariya, Ghardaïa, Timimoun, Kufrah, and
The central part of the Sahara is hyper-arid, with little
vegetation. The northern and southern reaches of the desert, along
with the highlands, have areas of sparse grassland and desert
shrub, with trees and taller shrubs in wadis where moisture
north, the Sahara reaches to the Mediterranean Sea in Egypt and portions
of Libya, but in
Cyrenaica and the Magreb, the Sahara borders Mediterranean forest,
woodland, and scrub ecoregions of northern Africa, which have a
characterized by a winter rainy season.
According to the
criteria of Frank White and
geographer Robert Capot-Rey
northern limit of the Sahara corresponds to the northern limit of
, and the southern limit of Esparto (Stipa tenacissima)
, a grass
typical of the Mediterranean climate portion of the Maghreb and
Iberia. The northern limit also corresponds to the isohyet
To the south, the Sahara is bounded by the Sahel
, a belt of dry tropical
with a summer rainy season that extends across Africa
from east to west. The southern limit of the Sahara is indicated
botanically by the southern limit of Cornulaca monacantha
drought-tolerant member of the Chenopodiaceae
), or northern limit of
typical of the Sahel
. According to climatic
criteria, the southern limit of the Sahara corresponds to the
isohyet of annual precipitation (note that this is a long-term
average, since precipitation
from one year to another).
The climate of the Sahara has undergone enormous variation between
wet and dry over the last few hundred thousand years. During the
last glacial period
, the Sahara was
even bigger than it is today, extending south beyond its current
boundaries. The end of the glacial period brought more rain to the
Sahara, from about 8000 BC to 6000 BC, perhaps due to low pressure areas
over the collapsing
to the north.
Once the ice sheets were gone, northern Sahara dried out. But in
southern Sahara, the drying trend was soon counteracted by the
, which brought rain further north
than it does today. The monsoon is due to heating of air over the
land during summer. The hot air rises and pulls in cool, wet air
from the ocean, which causes rain. Thus, though it seems
counterintuitive, the Sahara was wetter when it received more
in the summer. This was caused
by a stronger tilt in Earth's axis of
than today, and perihelion
at the end of July.
By around 3400 BC, the monsoon retreated south to approximately
where it is today, leading to the gradual desertification
of the Sahara. The Sahara is
now as dry as it was about 13,000 years ago. These conditions are
responsible for what has been called the Sahara pump theory
The Sahara has one of the harshest climates in the world. The
prevailing north-easterly wind often causes the sand to form
and dust devils
. Half of the Sahara receives less
than of rain per year, and the rest receives up to per year. The
rainfall happens very rarely, but when it does it is usually
when it occurs after long dry
periods, which can last for years.
The southern boundary of the Sahara, as measured by rainfall, was
observed to both advance and retreat between 1980 and 1990. As a
result of drought in the Sahel
southern boundary moved south overall during that period.. Deforestation
has also caused the Sahara to
advance south in recent years , as trees
continue to be used as fuel
Recent signals indicate that the Sahara and surrounding regions are
greening due to increased rainfall. Satellites show extensive
regreening of the Sahel between 1982 and 2002, and in both Eastern
and Western Sahara a more than 20 year long trend of increased
grazing areas and flourishing trees and shrubs has been observed by
climate scientist Stefan Kröpelin.
The Sahara comprises several distinct ecoregions
, whose variations in temperature,
rainfall, elevation, and soils harbor distinct communities of
plants and animals. According to the World Wide Fund for Nature
the ecoregions of the Sahara include:
coastal desert: The coastal desert occupies a narrow strip
along the Atlantic coast, where fog generated offshore by the cool
Canary Current provides sufficient
moisture to sustain a variety of lichens,
succulents, and shrubs.
39,900 square kilometers (15,400 square miles) in Western
Sahara and Mauritania.
- North Saharan
steppe and woodlands: This ecoregion lies along the northern
edge of the desert, next to the Mediterranean
forests, woodlands, and scrub ecoregions of the northern
Maghreb and Cyrenaica. Winter rains sustain shrublands and dry
woodlands that form a transition between the Mediterranean climate regions to the
north and the hyper-arid Sahara proper to the south. It covers 1,675,300
square km (646,800 square miles) in Algeria, Egypt, Libya, Mauritania,
Morocco, Tunisia, and Western Sahara.
- Sahara desert: This
ecoregion covers the hyper-arid central portion of the Sahara where
rainfall is minimal and sporadic. Vegetation is rare, and this
ecoregion consists mostly of sand dunes (erg, chech,
raoui), stone plateaus (hamadas), gravel plains
(reg), dry valleys (wadis), and salt flats.
4,639,900 square km (1,791,500 square miles) of Algeria, Chad, Egypt,
Libya, Mali, Mauritania,
Niger, and Sudan.
- South Saharan
steppe and woodlands: The South Saharan steppe and woodlands
occupy a narrow band running east and west between the hyper-arid
Sahara and the Sahel savannas to the south.
Movements of the equatorial Intertropical Convergence
Zone (ITCZ) bring summer rains during July and August which
average , but vary greatly from year to year. These rains sustain
summer pastures of grasses and herbs, with dry woodlands and
shrublands along seasonal watercourses. The ecoregion covers
1,101,700 square km (425,400 square miles) in Algeria, Chad, Mali,
Mauritania, and Sudan.
- West Saharan
montane xeric woodlands: Several volcanic highlands in the
western portion of the Sahara provide a cooler, moister environment
that supports Saharo-Mediterranean woodlands and shrublands.
ecoregion covers 258,100 square kilometers (99,700 square miles),
mostly in the Tassili
n'Ajjer of Algeria, with smaller enclaves in the Aïr of Niger, the Dhar Adrar of Mauritania, and the Adrar des Iforas of Mali and
Uweinat montane xeric woodlands: The Tibesti and Jebel
Uweinat highlands foster higher, more regular rainfall and
cooler temperatures, which support woodlands and shrublands of
Tamarix, and several rare and endemic
plants. The ecoregion covers 82,200 square km (31,700 square
miles) in the Tibesti of Chad and Libya, and Jebel Uweinat on the
border of Egypt, Libya, and Sudan.
- Saharan halophytics:
Seasonally-flooded saline depressions in the Sahara are home to
halophytic, or salt-adapted, plant
communities. The Saharan halophytics cover 54,000 square
km (20,800 square miles), including the Qattara and Siwa depressions
in northern Egypt, the Tunisian salt
lakes of central Tunisia, Chott Melghir in Algeria, and smaller areas of Algeria,
Mauritania, and Western Sahara..
- Tanezrouft: One of the harshest regions on Earth and the
driest in the Sahara, contains no vegetation and very little
Shadows of camels with travelers on
dunes in Tunisia
- Dromedary camels and goats are the most domesticated animals found in the
Sahara. Because of its qualities of sobriety, endurance and speed, the dromedary is the
favorite animal used by nomads.
- The Leiurus
quinquestriatus (aka deathstalker) scorpion which can be
long. Its venom contains large amounts of agitoxin and scyllatoxin
and is very dangerous; however, a sting from this scorpion rarely
kills a healthy adult.
- The monitor lizard. It has been
suggested that the occasional habit of varanids to stand on their
two hind legs and to appear to "monitor" their surroundings led to
the original Arabic name waral ورل, which is translated to
English as "monitor".
- Sand vipers, which average less
than in length. Many have a pair of horns, one over each eye.
Active at night, they usually lie buried in the sand with only
their eyes visible. Bites are painful, but rarely fatal.
- The African Wild Dog has some
populations confirmed in the southern Sahara and is frequently
misidentified as the cryptid Adjule.
- The fennec fox, pale fox and rüppell's fox, are omnivorous canids living in many parts of
- The hyrax. It first appears in the
fossil record over 40 million years ago, and
for many millions of years hyraxes were the primary terrestrial
herbivore in Africa.
- The ostrich which is a flightless bird native to Africa. They have
- The addax, a large white antelope, is a threatened species. Adapted to the
desert, they can remain months without drinking, even a whole
Saharan cheetah lives in Algeria, Togo, Niger, Mali, Benin, and
Faso. There remain less than 250 mature cheetahs
which are very cautious, fleeing any human presence. The cheetah
avoids the sun from April to October. It then seeks the shelter of
shrubs such as balanites and acacias. They are unusually pale.
- The dorcas gazelle is a north
African gazelle that can also go for a long time without
There exist other animals in the Sahara (birds in particular) such
as African Silverbill
Photo of the Sahara from 1908
are one of the oldest known
inhabitants of the Sahara Desert. They are the people that occupied
(and still occupy) more than two thirds of the Sahara's total
surface. The Garamantes
Berbers built a
prosperous empire in the heart of the desert. The Tuareg nomads continue, to present day, to inhabit
and move across wide Sahara surfaces in Algeria, Mali, Niger, Mauritania, and Libya.
of the oldest Berber Tifinagh
are found in Southern Algeria, Northern Mali and Niger.
By 6000 BC predynastic Egyptians
in the southwestern corner of Egypt were herding
cattle and constructing
large buildings. Subsistence in
organized and permanent settlement
predynastic Egypt by the middle of the 6th millennium BC centered
predominantly on cereal
and animal agriculture
objects replaced prior ones of stone
animal skins, pottery
are commonplace in this era also.
indications of seasonal or only temporary occupation of the
Fayyum in the 6th millennium BC, with food activities
centering on fishing, hunting and food-gathering.
are common. Burial
items include pottery, jewelry
, farming and hunting equipment, and assorted
foods including dried meat and fruit. Burial in desert environments
appears to enhance Egyptian preservation rites, and dead are buried
facing due west.By 3400 BC, the Sahara was as dry as it is today,
and it became a largely impenetrable barrier to humans, with only
scattered settlements around the oases, but little trade
or commerce through the desert. The one major
exception was the Nile Valley
. The Nile,
however, was impassable at several cataract
, making trade and contact by
During the Neolithic
, before the onset of
desertification, the central Sudan had been a rich environment
supporting a large population ranging across what is now barren
desert, like the Wadi el-Qa'ab. By the 5th millennium BC, the
peoples who inhabited what is now called Nubia
, were full participants in the "agricultural
revolution," living a settled lifestyle with domesticated plants
and animals. Saharan rock art of cattle and herdsmen
found suggests the presence of a cattle cult like those found in
Sudan and other pastoral societies in Africa
today. Megaliths found at Nabta Playa are overt examples of probably the world's first
known Archaeoastronomy devices,
predating Stonehenge by some 1000 years.
This complexity, as
observed at Nabta Playa, and as expressed by different levels of
authority within the society there, likely formed the basis for the
structure of both the Neolithic society at Nabta and the Old
Kingdom of Egypt.
peoples of Phoenicia, who flourished between 1200-800 BC, created a
confederation of kingdoms across the entire Sahara to Egypt.
They generally settled along the Mediterranean coast, as well as
the Sahara, among the peoples of Ancient
, who were the ancestors of peoples who speak Berber languages
in North Africa and the
Sahara today, including the Tuareg
The Phoenician alphabet seems to have been adopted by the ancient
Libyans of north Africa, and Tifinagh
still used today by Berber-speaking Tuareg camel herders of the
between 633 BC and 530 BC, Hanno the
Navigator either established or reinforced Phoenician colonies
Sahara, but all ancient remains have vanished with
virtually no trace.
(See History of Western Sahara
By 500 BC, a new influence arrived in the form of the Greeks
. Greek traders spread along the eastern coast
of the desert, establishing trading colonies along the Red Sea
coast. The Carthaginians explored the Atlantic coast of the desert.
turbulence of the waters and the lack of markets never led to an
extensive presence further south than modern Morocco.
Centralized states thus surrounded the
desert on the north and east; it remained outside the control of
these states. Raids from the nomadic Berber people
of the desert were a constant
concern of those living on the edge of the desert.
civilization, the Garamantes, arose
around this time in the heart of the Sahara, in a valley that is
now called the Wadi al-Ajal in Fazzan, Libya.
Garamantes achieved this development by digging tunnels far into
the mountains flanking the valley to tap fossil water
and bring it to their fields. The
Garamantes grew populous and strong, conquering their neighbors and
capturing many slaves (which were put to work extending the
tunnels). The ancient Greeks and the Romans
knew of the Garamantes and regarded them
as uncivilized nomads. However, they traded with the Garamantes,
and a Roman bath
has been found in the
Garamantes capital of Garama. Archaeologists
have found eight major towns and
many other important settlements in the Garamantes territory. The
Garamantes civilization eventually collapsed after they had
depleted available water in the aquifers
and could no longer sustain the effort to extend the tunnels still
further into the mountains.
Following the Islamic
conquest of North
Africa in the seventh century CE
across the desert intensified. The kingdoms of the Sahel
, especially the Ghana
and the later Mali Empire
grew rich and powerful exporting gold
to North Africa. The emirates along
Sea sent south manufactured goods and horses.
From the Sahara itself, salt
was exported. This process turned the
communities into trading
centres, and brought them under the control of the empires on the
edge of the desert. A significant slave trade crossed the desert
(See Arab slave trade
trade persisted for several centuries until the development in
Europe of the caravel allowed ships, first
from Portugal but soon from all Western Europe, to sail around
the desert and gather the resources from the source in Guinea.
The Sahara was rapidly
beginning of the 19th century, most of the northern Sahara,
including most of present-day Algeria, Tunisia, Libya, and
Egypt, was part of the Ottoman
The Sahel and southern Sahara were home to
several independent states.
European colonialism in the Sahara began in the 19th century.
Algeria from the Ottomans in 1830, and French rule spread south
from Algeria and eastwards from Senegal into the upper Niger to
include present-day Algeria, Chad, Mali, Mauritania, Morocco (1912), Niger, and
under Muhammad Ali and his
successors, conquered Nubia (1820-22), founded
Khartoum (1823), and conquered Darfur
Egypt, including the Sudan, became a British
protectorate in 1882. Egypt and Britain lost control of the Sudan
from 1882 to 1898 as a result of the Mahdist
. After its capture by British troops in 1898, the Sudan
became a Anglo-Egyptian condominium
Sahara after 1874. In 1912, Italy captured
Libya from the Ottomans.
To promote the Roman Catholic
religion in the desert, the Pope
appointed a delegate Apostolic of the Sahara and the Sudan; later
in the 19th century his jurisdiction was reorganized into the
Vicariate Apostolic of
A natural rock arch in south western
Egypt became independent of Britain in 1936, although the Anglo-Egyptian Treaty of 1936
allowed Britain to keep troops in Egypt and maintained the
British-Egyptian condominium in the Sudan. British military forces
were withdrawn in 1954.
Most of the Saharan states achieved independence after World War II
: Libya in 1951, Morocco, Sudan,
and Tunisia in 1956, Chad, Mali, Mauritania, and Niger in 1960, and
Algeria in 1962. Spain withdrew from Western Sahara in 1975, and it
was partitioned between Mauritania and Morocco. Mauritania withdrew
in 1979, but Morocco continues to hold the territory.
The modern era has seen a number of mines
communities develop to exploit the desert's natural resources.
include large deposits of oil and natural gas in Algeria and Libya and large deposits of phosphates in Morocco and Western
highways have been proposed across the Sahara, including the
Cairo-Dakar Highway along the
Atlantic coast, the Trans-Sahara
Highway from Algiers on the Mediterranean to Kano in
Nigeria, the Tripoli-Cape Town
Highway from Tripoli in Libya to Ndjamena in Chad, and the Cairo-Cape Town Highway which
follows the Nile.
Each of these highways is partially
complete, with significant gaps and unpaved sections.
Peoples and languages
The Sahara is home to a number of peoples and languages. Arabic
is the most widely spoken language in the
Sahara, from the Atlantic to the Red Sea. Berber people
are found from western Egypt to
Morocco, including the Tuareg
the central Sahara. The Beja
live in the
Red Sea Hills
of southeastern Egypt
and eastern Sudan. The Arabic, Berber, and Beja languages are part
of the Afro-Asiatic
of the Nilo-Saharan language family
also inhabit the Sahara, including the Fur of Darfur in western
Sudan and the Saharan languages of
Niger, Chad and western Sudan, which includes the Kanuri, Tedaga, and Dazaga.
Countries in the Sahara
The following countries are either fully or partially covered by
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