Lake Turkana, formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya (although the far northern end of the lake crosses into Ethiopia), which covers a surface area of 6405 km² (2473 mi²), making it the world's largest permanent desert lake. It is also the world's largest alkaline lake. The area is hot and very dry. The geology is predominantly volcanic and on-shore and off-shore winds can be extremely strong as the lake warms and cools more slowly than the land. Three rivers (the Omo, Turkwel and Kerio) flow into the lake, but the only outflow is by evaporation. Despite this, the water level of the lake fell by 10 m between 1975 and 1993.
The lake was named Lake Rudolf by Count Samuel Teleki and Lieutenant Von Höhnel in 1888, and renamed Lake Turkana in 1975. The area has been preserved by its remoteness and still sees few Western visitors, being a 3 day drive from Nairobi. Local people are predominantly of the Gabbra , Rendille and Turkana tribes. One of the villages surrounding the lake is El Molo.
Lake Turkana, sometimes referred to as the Jade Sea, contains Nile perch and tilapia, used to contain Africa's largest population of Nile crocodiles - 14,000 bred on Central Island. The presence of water in such an arid area makes the region internationally important as a staging post for migrating birds. Lions, cheetah and giraffe as well as many other species of mammal live in the area. Elephants and rhino are no longer seen, although Teleki reported seeing (and indeed shooting) many. Lake Turkana is now listed as a UNESCO World Heritage Site.
Richard Leakey has led numerous anthropological digs in the area which have led to many important discoveries of hominid remains. The 2 million year old Skull 1470 was found in 1972. It was originally thought to be Homo habilis but some anthropologists have assigned it to a new species, Homo rudolfensis, named after the lake. In 1984, the Turkana Boy, a nearly complete skeleton of a nine-year old Homo erectus boy was discovered.