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Chemistry LibreTexts

7.5: East Africa

  • Page ID
    148072
  • Learning Objectives

    1. Summarize the physical layout and features of East Africa, including the Great Rift Valley.
    2. Outline the significance that the wildlife and natural beauty of vast regions such as the Serengeti have for the economic activities of the region.
    3. Explain how each country in East Africa is different from the others and what geographic attributes they have in common.
    4. Analyze the affect the African Transition Zone has had on the Horn of Africa.
    5. Learn how and why the country of Somalia is divided into several political regions and what difficulties Somalia has to contend with.

    Physical Geography

    East Africa is a region that begins in Tanzania in the south and extends north through the great grasslands and scrub forest of the savannas of Kenya and Uganda and then across the highlands of Ethiopia, including the Great Rift Valley. The region also comprises the countries of Somalia, Djibouti, and Eritrea, which are located in the African Transition Zone between North Africa and Subsahran Africa. Rwanda and Burundi are physically in East Africa but are covered in the lesson about Central Africa because of their border activities with the Congo. The world’s second-largest lake by surface area is Lake Victoria, which borders Uganda, Tanzania, and Kenya. (Lake Superior, on the border between the United States and Canada, is considered the lake with the largest surface area.) Lake Victoria provides fish and fresh water for millions of people in the surrounding region. The White Nile starts at Lake Victoria and flows north to the city of Khartoum in Sudan, where it converges with the Blue Nile to become the Nile River. The source of the Blue Nile is Lake Tana in the highlands of Ethiopia.

    Figure 7.38 East Africa

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    The highest mountain in Africa, Mt. Kilimanjaro (19,340 feet), is located in Tanzania near the border with Kenya. The second highest peak, Mt. Kenya (17,058 feet), located just north of the country’s capital of Nairobi, near the equator, is the source of Kenya’s name. Both mountains are inactive volcanoes and have permanent snow at their peaks. They provide fresh water, which flows down their mountainsides, to the surrounding areas. Mountain ranges in the Western Highlands of the Congo have a greater effect on climate than these two massive peaks. For example, the Rwenzori Mountains on the Congo–Uganda border have permanent snow and glaciers and reach elevations of more than sixteen thousand feet. These ranges create a rain shadow effect that cuts off moisture for the region from the westerly equatorial winds.

    Figure 7.39 Great Rift Valley of East Africa

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    The African portion of the rift extends from Mozambique to the Red Sea. The valley is created by the movement of tectonic plates.

    This same effect is created by the highlands of Ethiopia, which reach as high as fifteen thousand feet in elevation and restrict precipitation in areas to the east. The lower level of rainfall transforms much of the region from a tropical rain forest into a savanna-type landscape with few forests, more open grasslands, and sporadic trees. Dry desert-like conditions can be found in a number of places along the Great Rift Valley.

    The Great Rift Valley

    The Great Rift Valley provides evidence of a split in the African Plate, dividing it into two smaller tectonic plates: the Somalian Plate and the Nubian Plate. The Great Rift Valley in East Africa is divided into the Western Rift and the Eastern Rift. The Western Rift runs along the border with the Congo. A series of deepwater lakes run along its valley. On the western edge of the Western Rift are the highlands, which have a series of high-elevation mountain ranges, including the Rwenzori Mountains, the highest in the series. The Virunga Mountains on the Congo–Uganda border are home to endangered mountain gorillas. The Western Rift includes a series of deepwater lakes, such as Lake Tanganyika, Lake Edward, and Lake Albert. Lake Victoria is located between the Western Rift and the Eastern Rift.

    The Eastern Rift does not have deepwater lakes; rather, it is a wide valley or basin with shallow lakes that do not have outlets. The lakes have higher levels of sodium carbonate and mineral buildup because of a high rate of evaporation. The differences in water composition of the lakes along the Eastern Rift vary from freshwater to extremely alkaline. Alkaline water creates an ideal breeding ground for algae and other species of fish, such as tilapia, which thrive in this environment. Millions of birds feed off the abundant supply of algae and fish. Birds attract other wildlife, which in turn creates a unique set of environmental ecosystems. The eastern edge of the Eastern Rift is home to the inactive volcanic peaks of Mt. Kilimanjaro and Mt. Kenya. A number of other volcanic peaks are present in the Eastern Rift, such as Ol Doinyo Lengai, an active volcano.

    The erosion patterns of the highlands have caused a buildup of sediments on the rift valley floor, creating a favorable environment for the preservation of biological remains, including both human and animal remains. Important fossils and bones of several hominid species have been found in the Great Rift Valley. One of the most famous finds came in 1974 when the nearly complete skeleton of an australopithecine nicknamed “Lucy.” Lucy was discovered by anthropologist Donald Johanson. Noted anthropologists Richard and Mary Leakey have also done significant work in this region. Since the 1970s, remains of hominids from about ten million years ago were discovered in the northern region of the Great Rift Valley. Discoveries at the thirty-mile-long Olduvai Gorge indicate that early hominid species might have lived in the region for millions of years.

    Figure 7.40 The Great Rift Valley

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    Hiking into the Great Rift Valley region in Tanzania.

    Serengeti and Game Reserves

    The Great Rift Valley and the surrounding savannas in Kenya and Tanzania are home to some of the largest game reserves in Africa, with a broad variety of big game animals. One of these large regions is the vast Serengeti Plain, located in northern Tanzania and southern Kenya. The governments of Tanzania and Kenya maintain national parks, national game reserves, and wildlife sanctuaries in their countries, most notably in the Serengeti Plain. Legal protection for as much as 80 percent of the Serengeti has been provided. The protections restrict hunting and commercial agriculture and provide protection status for the wildlife. The word Serengeti means “Endless Plains.”

    The Serengeti Plain is host to an extraordinary diversity of large mammals and fauna. The largest migration of land animals in the world occurs in the Serengeti. Every fall and spring, as many as two million wildebeests, antelope, and other grazing animals migrate from the northern hills to the southern plains in search of grass and food. The Ngorongoro Conservation Area, which is a UNESCO World Heritage Site, and the Ngorongoro Crater are located on the Tanzanian side of the border. The enormous crater is the basin of an extinct volcano that has been transformed into a protected national park for the animals that graze on the grassy plains. This is a dry region because the Ngorongoro Highlands create a rain shadow for the area.

    Figure 7.41 The Serengeti Plains in the Ngorongoro Crater, Tanzania

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    Dozens of other protected areas throughout Eastern Africa have been established in an effort to protect and sustain the valuable ecosystems for the large animals that have found their habitat encroached upon elsewhere by the ever-expanding human population. Kenya has more than fifty-five nationally protected areas that serve as parks, reserves, or sanctuaries for wildlife. The Amboseli National Reserve and Mt. Kenya National Park are two of the more well-known protected areas. The “big five” game animals—elephants, rhinoceroses, lions, leopards, and buffalo—and all the other unique animals found in the same ecosystems, translate into economic income from tourists from around the world that wish to experience this type of environment. The national park systems in Uganda and Ethiopia have made provisions to provide more sanctuaries for wildlife in areas where the human population is growing and the political situation has not always been stable.