Rusinga Island
Encyclopedia
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
at the mouth of the Winam Gulf
Winam Gulf
Winam Gulf is a significant extension of northeastern Lake Victoria into western Kenya.Formerly known as Kavirondo Gulf, Nyanza Gulf, and Lake Nyanza Gulf, it is a shallow inlet and is connected to the main lake by Rusinga Channel , which is partly masked from the main body of the lake by islands...
. Part of Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, it is linked to Mbita Point
Mbita Point
Mbita Point is a rural community in the province of Nyanza, Kenya, on the shores of Lake Victoria. It is home to the Thomas Odhiambo campus of the International Centre for Insect Physiology and Ecology . A public primary school formerly international and a clinic are also hosted by the Centre....
on the mainland by a causeway
Causeway
In modern usage, a causeway is a road or railway elevated, usually across a broad body of water or wetland.- Etymology :When first used, the word appeared in a form such as “causey way” making clear its derivation from the earlier form “causey”. This word seems to have come from the same source by...
.
Demography
The local language is LuoLuo (family of ethnic groups)
The Luo are an ethnic linguistic group located in an area that stretches from South Sudan and Ethiopia through northern Uganda and eastern Congo , into western Kenya, and ending in the upper tip of Tanzania. These people speak an Eastern Sudanic language, a branch of the Nilo-Saharan language...
, although the ancestors of the current inhabitants were Suba
Suba
-Groups of people:*Suba , a people of Kenya**Suba language*Suba , a people of Tanzania-Individual people:*Suba , Mitar Subotić, a Serbian-Brazilian musician*Mihai Șubă, Romanian chess grandmaster-Places:...
people who came in boats several hundred years ago from Uganda as refugees from a dynastic war. Many Rusinga place names betray Suba origins, including the island's name itself and its central peak, Lunene. There was an extinct language of Uganda called Singa, alternatives Lusinga and Lisinga, spoken only on Rusinga Island (which, of course is in Kenya). It belonged to the same group of Niger–Congo as Suba. As of 2006, estimates of Rusinga's population range between 20,000 and 30,000. The entire island is part of the Suba District
Suba District
Suba District is an administrative district in the Nyanza Province of Kenya. Its capital town is Mbita Point. The district has a population of 155,666 and an area of 1,055 km² . Suba district is named after the Suba people, who inhabit local Rusinga and Mfangano Islands.The district has two...
of Nyanza Province
Nyanza Province
Nyanza Province of Kenya, is one of Kenya's eight administrative provinces. It is located in the southwest part of Kenya around Lake Victoria. Nyanza includes part of the eastern edge of Lake Victoria and is inhabited predominantly by the Luo. There are also Bantu-speaking tribes such as the...
.
Most residents of Rusinga make their living from subsistence agriculture (maize and millet), as well as fishing. The native tilapia
Tilapia
Tilapia , is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats, including shallow streams, ponds, rivers and lakes. Historically, they have been of major importance in artisan fishing in Africa and the...
is still caught, though this species (like all others native to the lake) has been decimated by the voracious Nile perch
Nile perch
The Nile perch is a species of freshwaterfish in family Latidae of order Perciformes. It is widespread throughout muchof the Afrotropic ecozone, being native to the Congo, Nile, Senegal, Niger, and Lake Chad, Volta, Lake Turkana and other river basins. It also occurs in the brackish waters of...
that was introduced into the lake in 1954. Constant onshore winds cool the lakeward side of the island and provide clean beaches with ideal swimming and boating conditions, but poor roads between Rusinga and the nearest town, Homa Bay
Homa Bay
Homa Bay is a bay and town on the south shore of Winam Gulf of Lake Victoria, in western Kenya. It lies near Mount Homa and Ruma National Park, the latter noted for Jackson's hartebeests and roan antelope .Homa Bay was once the District...
, inhibit trade and tourism. The brightly glittering black sands of the beaches are made of crystals of melanite garnet
Garnet
The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...
, barkevikite hornblende
Hornblende
Hornblende is a complex inosilicate series of minerals .It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole....
, and magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
eroded from the uncompahgrite lava fragments in the agglomerate
Agglomerate
Agglomerates are coarse accumulations of large blocks of volcanic material that contain at least 75% bombs...
s that overlie the fossil beds.
The island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
is also notable as the family home and burial site of Tom Mboya
Tom Mboya
Thomas Joseph Odhiambo Mboya was a prominent Kenyan politician during Jomo Kenyatta's government. He was founder of the Nairobi People's Congress Party, a key figure in the formation of the Kenya African National Union , and the Minister of Economic Planning and Development at the time of his death...
, who before his assassination in 1969 was widely pegged as Jomo Kenyatta's successor as President of the new nation of Kenya.
Palaeontology
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
mammals, dated to 18 million years. The island had been only cursorily explored until the Leakey expedition of 1947-1948 began systematic searches and excavations, which have continued sporadically since then. The end of 1948 saw the collection of about 15,000 fossils from the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
, including 64 primates called by Louis Leakey
Louis Leakey
Louis Seymour Bazett Leakey was a British archaeologist and naturalist whose work was important in establishing human evolutionary development in Africa. He also played a major role in creating organizations for future research in Africa and for protecting wildlife there...
"Miocene apes."
All the species of Proconsul
Proconsul (genus)
Proconsul is an extinct genus of primates that existed from 23 to 5 million years ago during the Early Miocene epoch. Fossil remains are present in Eastern Africa including Kenya and Uganda. Four species have been classified to date: P. africanus, P. heseloni, P. major and P. nyanzae. The four...
were among the 64 and all were given the name africanus, although many were reclassified into nyanzae, major and heseloni later. Mary Leakey
Mary Leakey
Mary Leakey was a British archaeologist and anthropologist, who discovered the first skull of a fossil ape on Rusinga Island and also a noted robust Australopithecine called Zinjanthropus at Olduvai. For much of her career she worked together with her husband, Louis Leakey, in Olduvai Gorge,...
discovered the first complete skull of Proconsul, then considered a "stem hominoid", in 1948. Excavation of the fossil was completed by Louis' native assistant, Heselon Mukiri (whence Walker's 1993 name heseloni). Many thousands of fossils are now known from five major sites, with abundant hominoids including an almost complete skeleton of a second species of Proconsul, as well as Nyanzapithecus, Limnopithecus, Dendropithecus and Micropithecus, all of which show arboreal rather than terrestrial adaptations. The first true monkeys do not appear until around 15 million years, so it is widely supposed that the diverse Early Miocene African hominoids like those found on Rusinga filled that adaptive niche, and subsequently gave rise to both Cercopithecids
Old World monkey
The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous...
(Old World monkeys) and hominids (great apes and humans).
Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
mammal fossils, including an extinct antelope
Antelope
Antelope is a term referring to many even-toed ungulate species indigenous to various regions in Africa and Eurasia. Antelopes comprise a miscellaneous group within the family Bovidae, encompassing those old-world species that are neither cattle, sheep, buffalo, bison, nor goats...
known nowhere else, are also common in former shoreline deposits around the edges of the island, left behind as Lake Victoria has slowly subsided over the centuries due to erosion in its outlet.
Geology
The fossil beds are layers of volcanic ash produced by a succession of explosive eruptions during the earliest stages of a volcano that eventually covered an area 75 miles in diameter. The volcano is now eroded down to the frozen magma in its vent that makes up the Kisingiri hills on the mainland opposite Rusinga, and the surrounding remnants of the cone: the semicircular Rangwa mountain range, and the islands of Rusinga and neighboring Mfangano IslandMfangano Island
Mfangano Island lies in the eastern part of Lake Victoria, at the mouth of the Winam Gulf. Part of Kenya, it lies west of Rusinga Island. The island is 65 km² in area and rises to 1,694 m at Mount Kwitutu. It had a population of 16,282 as of 1999 census of population...
. This rift valley
Rift valley
A rift valley is a linear-shaped lowland between highlands or mountain ranges created by the action of a geologic rift or fault. This action is manifest as crustal extension, a spreading apart of the surface which is subsequently further deepened by the forces of erosion...
volcano on the southern flank of the now-inactive Winam Gulf tapped much deeper in the mantle than oceanic or subduction zone volcanos, and its lavas and explosive ash clouds thus contained much more carbonate and alkali than normal. This meant that even though the Miocene environment was a tropical rainforest, the chemistry of the successive ash beds was that of a desert dry lake, preserving everything from caterpillars and berries to apes and elephants in an unusual situation found only in a few other East African ex-volcanos, notably Menengai
Menengai
Menengai Crater is a massive shield volcano inside one of the biggest calderas in the world, located in the Great Rift Valley, Kenya. Farmland occupies its flanks.Menengai is located north of Nakuru, the third-biggest city in Kenya....
and Homa Mountain in western Kenya, Napak
Napak
Napak is a town in Northern Uganda. It is the commercial, administrative and municipal headquarters of Napak District. The district is named after the town.-Location:...
and Mount Elgon
Mount Elgon
Mount Elgon is an extinct shield volcano on the border of Uganda and Kenya, north of Kisumu and west of Kitale.- Physical features :It is the oldest and largest solitary volcano in East Africa, covering an area of around 3500 km²....
in Uganda, and the much younger Ol Doinyo Lengai
Ol Doinyo Lengai
Ol Doinyo Lengai is an active volcano located in the north of Tanzania and is part of the volcanic system of the Great Rift Valley in Eastern Africa. It is located in the eastern Rift Valley, south of both Lake Natron and Kenya. It is unique among active volcanoes in that it produces...
in Tanzania, which created the fossil beds of Olduvai Gorge
Olduvai Gorge
The Olduvai Gorge is a steep-sided ravine in the Great Rift Valley that stretches through eastern Africa. It is in the eastern Serengeti Plains in northern Tanzania and is about long. It is located 45 km from the Laetoli archaeological site...
.
See also
- Lake VictoriaLake VictoriaLake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
- Louis LeakeyLouis LeakeyLouis Seymour Bazett Leakey was a British archaeologist and naturalist whose work was important in establishing human evolutionary development in Africa. He also played a major role in creating organizations for future research in Africa and for protecting wildlife there...
- List of fossil sites (with link directory)
External links
- GEF RUSINGA ISLAND Projects, United Nations Development Programmes.
- Greening Rusinga Island, Africa Now site.
- Palaeoenvironments of Early Miocene Kisingiri volcano Proconsul sites: Evidence from carbon isotopes, palaeosols and hydromagmatic deposits, article by Erick Bestland and Evelyn Krull, Journal of the Geological Society, September, 1999. An extensive abstract of this highly technical article is displayed at no charge.