112-543: Central Island , also known as Crocodile Island , is a volcanic island located in the middle of Lake Turkana in Kenya. It is also the location of Central Island National Park , which is governed by the Kenya Wildlife Service . Central Island is composed of more than a dozen craters and cones, three of which are filled by small lakes. The two largest lakes partially fill craters up to a kilometre wide and about 80 m deep,
224-488: A Hungarian and an Austrian , on 6 March 1888. They were the first Europeans to have recorded visiting the lake after a long safari across East Africa. The lake kept its European name during the colonial period of British East Africa . However, the existence of the lake and its shape and location were well known in Europe long before Teleki conceived of his visit. At some unknown time, the lake acquired an alternative name as
336-533: A nameplate capacity of 850 kilowatts. As of October 2016 155 turbines had been installed with completion expected in 2017. It will be the largest wind power project in Africa. Full commercial operation achieved in March 2019. 100% Capacity Factor (meaning full 310 MW generated) achieved in March 2021. The Gibe III dam is already under construction by Ethiopia along its Omo River, with general recognition that it will cause
448-437: A 1968 study by Alistair Graham. The lake also has a large population of large water turtles, particularly in the area of Central Island. The Turkana mud turtle is endemic to the lake. Over the dry grasslands ranges a frail population of grazing mammals and predators. The grazers are chiefly Grevy's zebra , Burchell's zebra , the beisa oryx , Grant's gazelle , the topi and the reticulated giraffe . They are hunted by
560-511: A crocodile would kill most vertebrates. However, exertion by crocodilians can lead to death due to increasing lactic acid to lethal levels, which in turn leads to failure of the animal's internal organs. This is rarely recorded in wild crocodiles, normally having been observed in cases where humans have mishandled crocodiles and put them through overly extended periods of physical struggling and stress. The mouths of Nile crocodiles are filled with 64 to 68 sharply pointed, cone-shaped teeth (about
672-728: A dark bronze colouration above, with faded blackish spots and stripes variably appearing across the back and a dingy off-yellow on the belly, although mud can often obscure the crocodile's actual colour. The flanks, which are yellowish-green in colour, have dark patches arranged in oblique stripes in highly variable patterns. Some variation occurs relative to environment; specimens from swift-flowing waters tend to be lighter in colour than those dwelling in murkier lakes or swamps, which provides camouflage that suits their environment, an example of clinal variation. Nile crocodiles have green eyes. The colouration also helps to camouflage them; juveniles are grey, multicoloured, or brown, with dark cross-bands on
784-558: A distinct species, the West African (or desert) crocodile. The distributional boundaries between these species were poorly understood, but following several studies, they are now better known. West African crocodiles are found throughout much of West and Central Africa, ranging east to South Sudan and Uganda where the species may come into contact with the Nile crocodile. Nile crocodiles are absent from most of West and Central Africa, but range into
896-416: A dozen less than alligators have). For most of a crocodile's life, broken teeth can be replaced. On each side of the mouth, five teeth are in the front of the upper jaw ( premaxilla ), 13 or 14 are in the rest of the upper jaw ( maxilla ), and 14 or 15 are on either side of the lower jaw ( mandible ). The enlarged fourth lower tooth fits into the notch on the upper jaw and is visible when the jaws are closed, as
1008-531: A dry riverbed, the Lomekwi 3 site recovered primitive hammers, anvils, and cutting tools. However, the emergence of Acheulean technology no longer assumes that tool use was a distinguishing factor among Homo species as Australopithecus afarensis were also using simple tools prior to the appearance of the genus Homo , over 3.3 million years ago. Australopithecus anamensis fossils discovered by Meave Leakey in 1994 date to around 4 million years ago, setting
1120-408: A few minutes at a time, but can swim under water up to 30 minutes if threatened. If they remain fully inactive, they can hold their breath for up to 2 hours (which, as aforementioned, is due to the high levels of lactic acid in their blood). They have a rich vocal range and good hearing . Nile crocodiles normally crawl along on their bellies, but they can also "high walk" with their trunks raised above
1232-418: A further drop in the lake level.[29] Friends of Lake Turkana, a Kenyan organisation representing indigenous groups in northwestern Kenya whose livelihoods are linked to Lake Turkana, had previously estimated that the dam could reduce the level of Lake Turkana by up to 10 meter affecting up to 300,000 people.[30] This could cause the brackish water to increase in salinity to where it may no longer be drinkable by
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#17330930627321344-629: A high risk for a magnitude 7 or 8 earthquake in the Gibe III dam region. The magnitude of the impact that the dam and possible irrigation projects induced by the dam will have on the water level of Lake Turkana is controversial. A hydrological study conducted for the African Development Bank in November 2010 concluded that the filling of the dam will reduce the lake's water level by two metres, if no irrigation will be undertaken. Irrigation would cause
1456-784: A large number of gastroliths. One crocodile measuring 3.84 m (12 ft 7 in) and weighing 239 kg (527 lb) had 5.1 kg (11 lb) of stones in its stomach, perhaps a record gastrolith weight for a crocodile. Specimens shot near Mpondwe on the Semliki River had gastroliths in their stomach despite being shot miles away from any sources for the stones; the same holds true for specimens from Kafue Flats , Upper Zambezi and Bangweulu Swamp , all of which often had stones inside them despite being nowhere near stony regions. Cott (1961) felt that gastroliths were most likely serving as ballast to provide stability and additional weight to sink in water, this bearing great probability over
1568-527: A major decrease in river flow downstream and a serious reduction of inflow to Kenya's Lake Turkana, which receives 90 per cent of its waters from the river. According to the ARWG [citation needed] report, these changes will destroy the survival means of at least 200,000 pastoralists, flood-dependent agriculturalists and fishers along the Omo River 300,000 pastoralists and fishers around the shores of Lake Turkana – plunging
1680-590: A period of time, but hunt by themselves and are not fed by the parents. The Nile crocodile is one of the most dangerous species of crocodile and is responsible for hundreds of human deaths every year. It is common and is not endangered, despite some regional declines or extirpations in the Maghreb . The binomial name Crocodylus niloticus is derived from the Greek κρόκη, kroke ("pebble"), δρῖλος, drilos ("worm"), referring to its rough skin; and niloticus , meaning "from
1792-441: A powerful bite that is unique among all animals, and sharp, conical teeth that sink into flesh, allowing a grip that is almost impossible to loosen. They can apply high force for extended periods of time, a great advantage for holding down large prey underwater to drown. Nile crocodiles are relatively social. They share basking spots and large food sources, such as schools of fish and big carcasses . Their strict hierarchy
1904-557: A profound influence on the level of Lake Turkana and adjacent water bodies. The archaeoastronomical site Namoratunga which has been dated circa 300 BC is located near Lake Turkana. Hominin fossils of some of the earliest human ancestors have been found in the Turkana Basin. Lake Turkana is considered the cradle of human life because of the diverse hominid species found living millions of years apart, in this desert landscape. These fossils have facilitated our understanding of
2016-450: A separate species). In a study of the morphology of the various populations, including C. (n.) suchus , the appearance of the Nile crocodile sensu lato was found to be more variable than that of any other currently recognized crocodile species, and at least some of these variations were related to locality. For example, a study on Lake Turkana in Kenya (informally this population would be placed in C. n. pauciscutatus ) found that
2128-535: A similar length. As an example of the body mass increase undergone by mature crocodiles, one of the larger crocodiles handled firsthand by Cott (1961) was 4.4 m (14 ft 5 in) and weighed 414.5 kg (914 lb), while the largest specimen measured by Graham and Beard (1973) was 4.8 m (15 ft 9 in) and weighed more than 680 kg (1,500 lb). One of the largest known specimens from South Africa , caught by J. G. Kuhlmann in Venda , which
2240-667: A single source of the introduction. This source remains unclear, as their genetics do not match samples collected from captives at various zoos and theme parks in Florida. When compared to Nile crocodiles from their native Africa, the Florida wild specimens are most closely related to South African Nile crocodiles. It is unknown how many Nile crocodiles are currently at large in Florida. The animals likely were either brought there to be released or are escapees. Generally, Nile crocodiles are relatively inert creatures, as are most crocodilians and other large, cold-blooded creatures. More than half of
2352-436: A source of diseases spread by contaminated water. Increasingly, communities on the lake's shores rely on underground springs for drinking water. The same characteristics that make it unsuitable for drinking limit its use in irrigation . The climate is hot and very dry. The rocks of the surrounding area are predominantly volcanic . Central Island is an active volcano, emitting vapour. Outcrops and rocky shores are found on
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#17330930627322464-463: A specialization at hunting sizeable prey, such as large mammals and freshwater turtles, the latter much larger than any in present-day Africa. Studies have since shown these other African crocodiles to be only more distantly related to the Nile crocodile. Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological , molecular ( DNA sequencing ), and stratigraphic ( fossil age) data, as revised by
2576-462: A specimen measuring 5.36 m (17 ft 7 in) in total length (with a considerable portion of its tail tip missing). The weight of this specimen was estimated to be 838 kg (1,847 lb), making it one of the largest crocodiles ever to be captured and released alive. The bulk and mass of individual crocodiles can be fairly variable, some animals being relatively slender, while others being very robust; females are often bulkier than males of
2688-408: A variety of prey, with a diet consisting mostly of different species of fish, reptiles, birds, and mammals . As ambush predators , they can wait for hours, days, and even weeks for the suitable moment to attack. They are agile predators and wait for the opportunity for a prey item to come well within attack range. Even swift prey are not immune to attack. Like other crocodiles, Nile crocodiles have
2800-446: Is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa , occurring mostly in the eastern, southern, and central regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps and marshlands . It occasionally inhabits deltas , brackish lakes and rarely also saltwater. Its range once stretched from
2912-524: Is a saline lake in the Kenyan Rift Valley , in northern Kenya , with its far northern end crossing into Ethiopia . It is the world's largest permanent desert lake and the world's largest alkaline lake . By volume it is the world's fourth-largest salt lake after the Caspian Sea , Issyk-Kul , and Lake Van (passing the shrinking South Aral Sea ), and among all lakes it ranks 24th. Lake Turkana
3024-422: Is clearly a deliberate behaviour for the species, the purpose is not definitively known. Gastroliths are not present in hatchlings, but increase quickly in presence within most crocodiles examined at 2–3.1 m (6 ft 7 in – 10 ft 2 in) and yet normally become extremely rare again in very large specimens, meaning that some animals may eventually expel them. However, large specimens can have
3136-464: Is concentrated along the NE-to-SE rim of the central crater, and sprays of sulfur from the fumaroles were observed by visitors in the 1930s. In 1974 intense emission of molten sulfur and steam clouds were seen from the mainland. This Kenya location article is a stub . You can help Misplaced Pages by expanding it . Lake Turkana Lake Turkana ( / t ɜːr ˈ k ɑː n ə , - ˈ k æ n -/ )
3248-482: Is determined by size. Large, old males are at the top of this hierarchy and have first access to food and the best basking spots. Crocodiles tend to respect this order; when it is infringed, the results are often violent and sometimes fatal. Like most other reptiles, Nile crocodiles lay eggs ; these are guarded by the females but also males, making the Nile crocodiles one of few reptile species whose males contribute to parental care. The hatchlings are also protected for
3360-569: Is now threatened by the construction of the Gilgel Gibe III Dam in Ethiopia due to the damming of the Omo river which supplies most of the lake's water. Although the lake commonly has been—and to some degree still is—used for drinking water, its salinity (slightly brackish ) and very high levels of fluoride (much higher than in fluoridated water ) generally make it unsuitable, and it has also been
3472-406: Is sensitive to climatic and seasonal fluctuations. For purposes of comparison, the historic level of Lake Turkana declined from a high of 20m above today's level in the 1890s to the same level as today in the 1940s and 1950s. Then it increased again gradually by 7 metres to reach a peak around 1980, and subsequently decreased again.[31] The Environmental and Social Impact Assessment (ESIA) summary of
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3584-402: Is the case with all true crocodiles. Hatchlings quickly lose a hardened piece of skin on the top of their mouths called the egg tooth , which they use to break through their eggshells at hatching. Among crocodilians, the Nile crocodile possesses a relatively long snout, which is about 1.6 to 2.0 times as long as broad at the level of the front corners of the eyes. As is the saltwater crocodile,
3696-479: Is the largest predator in Africa, and may be considered the second-largest extant reptile in the world, after the saltwater crocodile ( Crocodylus porosus ). Size is sexually dimorphic , with females usually about 30% smaller than males. The crocodile has thick, scaly, heavily armoured skin. Nile crocodiles are opportunistic apex predators ; a very aggressive crocodile, they are capable of taking almost any animal within their range. They are generalists , taking
3808-675: The Central African Republic , the Democratic Republic of the Congo , Equatorial Guinea , Tanzania, Rwanda , Burundi , Zambia, Zimbabwe , Gabon , Angola , South Africa, Malawi , Mozambique , Namibia , Sudan , South Sudan , Botswana , and Cameroon . The Nile crocodile's current range of distribution extends from the regional tributaries of the Nile in Sudan and Lake Nasser in Egypt to
3920-722: The Cunene river of Angola, the Okavango Delta of Botswana, and the Olifants River in South Africa. Isolated populations also exist in Madagascar , which were supposed to have likely colonized the island very recently, after the extinction of the endemic crocodile Voay within the last 2000 years . However in 2022 a skull of Crocodylus from Madagascar was found to be around 7,500 years old based on radiocarbon dating, suggesting that
4032-671: The Jade Sea from its turquoise colour seen approaching from a distance. The colour comes from algae that rise to the surface in calm weather. This is likely also a European name. J. W. Gregory reported in The Geographical Journal of 1894 that it was called "Basso Narok", meaning "Black Lake" in the Samburu language . Likewise, the nearby Ethiopian Lake Chew Bahir is called "Basso Naibor" in Samburu, meaning "White Lake". The Samburu are among
4144-602: The Nile Delta throughout the Nile River . Lake Turkana in Kenya has one of the largest undisturbed Nile crocodile populations. Generally, the adult male Nile crocodile is between 3.5 and 5 m (11 ft 6 in and 16 ft 5 in) in length and weighs 225 to 750 kg (496 to 1,653 lb). However, specimens exceeding 6.1 m (20 ft) in length and 1,000 kg (2,200 lb) in weight have been recorded. It
4256-653: The Turkana Basin . The highest is 100 m above the surface of the lake (only approximate, as the lake level fluctuates), which occurred about 9500 years ago, at the end of the Pleistocene as part of the African humid period . It is generally theorised that Turkana was part of the upper Nile system at that time, connecting to Lake Baringo at the southern end and the White Nile in the north, and that volcanic land adjustments severed
4368-518: The genus Crocodylus appear to be closely related to the Nile crocodile: C. anthropophagus from Plio-Pleistocene Tanzania and C. thorbjarnarsoni from Plio-Pleistocene Kenya . C. anthropophagus and C. thorbjarnarsoni were both somewhat larger, with projected total lengths up to 7.5–7.6 m (24 ft 7 in – 24 ft 11 in). As well as being larger, C. anthropophagus and C. thorbjarnarsoni , as well as Rimasuchus spp., were all relatively broad-snouted, indicating
4480-495: The little stint , the wood sandpiper , and the common sandpiper . The African skimmer ( Rhyncops flavirostris ) nests in the banks of Central Island. The white-breasted cormorant ( Phalacrocorax lucidus ) ranges over the lake, as do many other waterbirds. The greater flamingo wades in its shallows. Heuglin's bustard ( Neotis heuglinii ) is found in the east of the lake region. The lake formerly contained Africa's largest population of Nile crocodiles : 14,000, as estimated in
4592-558: The mantle , began separating from the rest of Africa, moving to the northeast. Currently, the graben is 320 km wide in the north of the lake, 170 km in the south. This rift is one of two, and is called the Great or Eastern Rift. There is another to the west, the Western Rift. Lake Turkana is a unique feature of the East African landscape. Besides being a permanent desert lake, it is
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4704-568: The saltwater crocodile . Typical size has been reported to be as much as 4.5 to 5.5 m (14 ft 9 in to 18 ft 1 in), but this is excessive for actual average size per most studies and represents the upper limit of sizes attained by the largest animals in a majority of populations. Alexander and Marais (2007) give the typical mature size as 2.8 to 3.5 m (9 ft 2 in to 11 ft 6 in); Garrick and Lang (1977) put it at from 3.0 to 4.5 m (9 ft 10 in to 14 ft 9 in). According to Cott (1961),
4816-1021: The 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay . Voay † Crocodylus anthropophagus † Crocodylus thorbjarnarsoni † Crocodylus palaeindicus † Crocodylus Tirari Desert † Crocodylus johnstoni Freshwater crocodile [REDACTED] Crocodylus novaeguineae New Guinea crocodile Crocodylus mindorensis Philippine crocodile Crocodylus porosus Saltwater crocodile [REDACTED] Crocodylus siamensis Siamese crocodile [REDACTED] Crocodylus palustris Mugger crocodile [REDACTED] Crocodylus checchiai † Crocodylus falconensis † Crocodylus suchus West African crocodile Crocodylus niloticus Nile crocodile [REDACTED] Crocodylus moreletii Morelet's crocodile Crocodylus rhombifer Cuban crocodile [REDACTED] Crocodylus intermedius Orinoco crocodile Crocodylus acutus American crocodile [REDACTED] Adult Nile crocodiles have
4928-816: The East African Nile crocodile), C. n. chamses (the West African Nile crocodile), C. n. cowiei (the South African Nile crocodile), C. n. madagascariensis (the Malagasy or Madagascar Nile crocodile, regionally also known as the croco Mada , which translates to Malagasy crocodile), C. n. niloticus (the Ethiopian Nile crocodile; this would be the nominate subspecies), C. n. pauciscutatus (the Kenyan Nile crocodile) and C. (n.) suchus (now widely considered
5040-790: The Mediterranean coast in Libya , Tunisia , Algeria , Morocco , the Nile Delta of Egypt and across the Red Sea in Palestine and Syria . The Nile crocodile has historically been recorded in areas where they are now regionally extinct. For example, Herodotus recorded the species inhabiting Lake Moeris in Egypt. They are thought to have become extinct in the Seychelles in the early 19th century (1810–1820). Today, Nile crocodiles are widely found in, among others, Somalia , Ethiopia , Uganda , Kenya, Egypt,
5152-1000: The Nile River". The Nile crocodile is called timsah al-nil in Arabic , mamba in Swahili , yaxaas in Somali , garwe in Shona , ngwenya in Ndebele , ngwena in Venda , kwena in Sotho and Tswana , and tanin ha-yeor in Hebrew . It also sometimes referred to as the African crocodile , Ethiopian crocodile , and common crocodile . Although no subspecies are currently formally recognized, as many as seven have been proposed, mostly due to variations in appearance and size noted in various populations throughout Africa. These have consisted of C. n. africanus (informally named
5264-433: The Nile crocodile is a quadruped with four short, splayed legs, a long, powerful tail , a scaly hide with rows of ossified scutes running down its back and tail, and powerful, elongated jaws . Their skin has a number of poorly understood integumentary sense organs that may react to changes in water pressure , presumably allowing them to track prey movements in the water. The Nile crocodile has fewer osteoderms on
5376-464: The Nile crocodile is considered a species with medium-width snout relative to other extant crocodilian species. In a search for the largest crocodilian skulls in museums, the largest verifiable Nile crocodile skulls found were several housed in Arba Minch , Ethiopia , sourced from nearby Lake Chamo , which apparently included several specimens with a skull length more than 65 cm (26 in), with
5488-593: The Turkana land. The area is primarily clay-based and is more alkaline than seawater. After the independence of Kenya , the president, Mzee Jomo Kenyatta , renamed it in 1975 after the Turkana , the predominant tribe there. The Turkana refer to the lake as Anam Ka'alakol , meaning "the sea of many fish". It is from the name Ka'alakol that Kalokol , a town on the western shore of Lake Turkana, east of Lodwar , derives its name. The previous indigenous Turkana name for Lake Turkana
5600-591: The area around Lake Turkana, which is evidence for numerous migrations of diverse people over thousands of years. The current language groups include at least three separate subgroups of the Nilotic ( Nilo-Saharan ) and Cushitic ( Afro-Asiatic ) language families, which have further subdivided into more than 12 languages surrounding the lake today. In the early Holocene (during the Holocene Climatic Optimum ), lake levels were high and fishing and foraging were
5712-473: The average female specimen would weigh 40 to 250 kg (88 to 551 lb). An old male individual, named "Big Daddy", housed at Mamba Village Centre, Mombasa , Kenya , is considered to be one of the largest living Nile crocodiles in captivity. It measures 5 m (16 ft 5 in) in length and weighs 800 kg (1,800 lb). In 2007, at the Katavi National Park , Brady Barr captured
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#17330930627325824-538: The average length and weight of Nile crocodiles from Uganda and Zambia in breeding maturity was 3.16 m (10 ft 4 in) and 137.5 kg (303 lb). Per Graham (1968), the average length and weight of a large sample of adult crocodiles from Lake Turkana (formerly known as Lake Rudolf), Kenya was 3.66 m (12 ft 0 in) and body mass of 201.6 kg (444 lb). Similarly, adult crocodiles from Kruger National Park reportedly average 3.65 m (12 ft 0 in) in length. In comparison,
5936-403: The beginning date of bipedalism back half a million years. Richard Leakey has led numerous anthropological expeditions in the area which have led to many important discoveries of hominin remains. The two-million-year-old skull 1470 was found in 1972. It was originally thought to be Homo habilis , but the scientific name Homo rudolfensis , derived from the old name of this lake (Rudolf)
6048-402: The belly, which are much more conspicuous on some of the more modestly sized crocodilians. The species, however, also has small, oval osteoderms on the sides of the body, as well as the throat. The Nile crocodile shares with all crocodilians a nictitating membrane to protect the eyes and lachrymal glands to cleanse its eyes with tears. The nostrils , eyes, and ears are situated on the top of
6160-516: The cichlids Haplochromis macconneli , H. rudolfianus , H. turkanae and Hemichromis exsul , the barb Enteromius turkanae , the catfish Chrysichthys turkana , the robber tetras Brycinus ferox and B. minutus , the Rudolf lates Lates longispinis , the lampeyes Lacustricola jeanneli and Micropanchax rudolfianus , and the cyprinid Neobola stellae . Non-endemics include species such as Nile tilapia , mango tilapia , bichirs ,
6272-566: The connection. Such a hypothesis explains the Nile species in the lake, such as the crocodiles and the Nile perch. High water levels also occurred approximately 9000, 6000 and 5000 years ago, each of which were followed by drops in lake level of more than 40m in less than 200 years. It is thought that changes in the position of the Congo Air Boundary affected the ability of moisture from the Atlantic Ocean to reach eastern Africa, which had
6384-616: The crocodile's blood. Guggisberg (1972) had seen examples of birds picking scraps of meat from the teeth of basking crocodiles (without entering the mouth) and prey from soil very near basking crocodiles, so felt it was not impossible that a bold, hungry bird may occasionally nearly enter a crocodile's mouth, but not likely as a habitual behaviour. MacFarland and Reeder, reviewing the evidence in 1974, found that: "Extensive observations of Nile crocodiles in regular or occasional association with various species of potential cleaners (e.g. Plovers , Sandpipers , water dikkop ) ... have resulted in only
6496-480: The crocodiles observed by Cott (1961), if not disturbed, spent the hours from 9:00 a.m. to 4:00 p.m. continuously basking with their jaws open if conditions were sunny. If their jaws are bound together in the extreme midday heat, Nile crocodiles may easily die from overheating. Although they can remain practically motionless for hours on end, whether basking or sitting in shallows, Nile crocodiles are said to be constantly aware of their surroundings and aware of
6608-580: The crocodiles of the Americas, namely the American ( C. acutus ), Cuban ( C. rhombifer ), Morelet's ( C. moreletii ), and Orinoco crocodiles ( C. intermedius ). The fossil species C. checchiai from the Miocene in Kenya was about the same size as the extant African Nile crocodiles and shared similar physical characteristics to this specific species. At one time, the fossil species Rimasuchus lloydi
6720-483: The dominant tribes in the lake Turkana region when the explorers came." What the native form of this phrase was, what it might mean, and in which language is not clear. The major biomes are the lake itself, which is an aquatic biome, and the surrounding region, which is classified as desert and xeric shrubland . The Chalbi Desert is east of the lake. During moister times, a dry grassland appears, featuring Aristida adcensionis and A. mutabilis . During drier times,
6832-436: The dynamic human evolution process and implies that they descended from more than one common ancestor, diverging into multiple lineages. The changing forest environment forced the early humans to adapt to a more open grassland that increased their exposure to threatening predators. Volcanic ash and drier climates were ideal for preserving these human fossils but it also caused the lake to shrink or disappear at times. In
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#17330930627326944-521: The east and south shores of the lake, while dunes, spits and flats are on the west and north, at a lower elevation. On-shore and off-shore winds can be extremely strong, as the lake warms and cools more slowly than the land. Sudden, violent storms are frequent. Three rivers (the Omo , Turkwel and Kerio ) flow into the lake, but lacking outflow , its only water loss is by evaporation. Lake volume and dimensions are variable. For example, its level fell by 10 m (33 ft) between 1975 and 1993. Despite
7056-551: The eastern shore at the Nataruk Site, this region provides considerable insight to the way these early humans thrived and survived the inconsistent climate along the lake shore and beyond. Homo erectus is the closest of Homo sapiens ' ancestors and contended to be the first hominin to cross the Levantine corridor out of Africa, into Europe and Asia 1.8 million years ago. Many language groups are represented in
7168-528: The elephantfish Mormyrus kannume , African arowana , African knifefish , Distichodus niloticus , the Nile perch and numerous others. During the early Holocene , the water level of the lake was higher, and it overflowed into the Nile River, allowing fish and crocodiles access. Consequently, the non-endemic fishes in the lake are mainly riverine species of Nilotic origin. Some of the non-endemics do not breed in
7280-536: The extinction of Voay post-dates the arrival of Nile crocodiles on Madagascar. Nile Crocodiles occur in the western and southern parts of Madagascar from Sambirano to Tôlanaro . They have been spotted in Zanzibar and the Comoros in modern times, but occur very rarely. The species was previously thought to extend in range into the whole of West and Central Africa, but these populations are now typically recognized as
7392-572: The female is 3.05 m (10 ft 0 in), at which females would average about 116 kg (256 lb). This gives the Nile crocodile somewhat of a size advantage over the next largest non-marine predator on the African continent, the lion ( Panthera leo ), which averages 188 kg (414 lb) in males and 124 kg (273 lb) in females, and attains a maximum known weight of 313 kg (690 lb), far less than that of large male crocodiles. Nile crocodiles from cooler climates, like
7504-558: The firm that builds the dam this would reduce the water level in the lake by "less than 50 cm per year for three years" and that salinity "will not change in any way".[26] According to the International Lake Environment Committee, 90% of Lake Turkana's water is delivered by the Omo River on which the Dam would be built.[31] With no outlet, Lake Turkana loses 2.3 meters of water every year to evaporation, and its level
7616-564: The floors of which are near sea level. The highest point on the dominantly basaltic island reaches 550 m, about 190 m above the lake surface. An E-W-trending chain of small explosion craters cuts the eastern side of the 3-km-wide island. Several small islands to the SE represent partially submerged crater rims, and other cones and lava plugs lie beneath the lake surface near the island. The youngest Central Islands tuffs and lavas may be as young as Holocene (Karson and Curtis, 1992). Fumarolic activity
7728-695: The grass disappears. The shrublands contain dwarf shrubs, such as Duosperma eremophilum and Indigofera spinosa . Near the lake are doum palms . Both phytoplankton and zooplankton are found in the lake. Of the former, cyanobacteria are represented by Microcystis aeruginosa and microalgae by Botryococcus braunii . Also present are Anabaenopsis arnoldii , Planctonema lauterbornii , Oocystis gigas , Sphaerocystis schroeteri , and some others. The zooplankton includes copepods , cladocerans and protozoans . Compared to other large African lakes, Turkana has relatively few fish species. The lake holds about 50 fish species, including 12 endemics :
7840-564: The ground. Smaller specimens can gallop , and even larger individuals are capable of occasional, surprising bursts of speed, briefly reaching up to 14 km/h (8.7 mph). They can swim much faster, moving their bodies and tails in a sinuous fashion, and they can sustain this form of movement much longer than on land, with a maximum known swimming speed of 30 to 35 km/h (19 to 22 mph). Nile crocodiles have been widely known to have gastroliths in their stomachs, which are stones swallowed by animals for various purposes. Although this
7952-509: The head, so the rest of the body can remain concealed under water. They have a four-chambered heart , although modified for their ectothermic nature due to an elongated cardiac septum, physiologically similar to the heart of a bird, which is especially efficient at oxygenating their blood. As in all crocodilians, Nile crocodiles have exceptionally high levels of lactic acid in their blood, which allows them to sit motionless in water for up to 2 hours. Levels of lactic acid as high as they are in
8064-441: The indigenous groups around the lake. Currently, the salinity of the water is about 2332 mg/L, and it is estimated that a 10-meter decrease in the water level of Lake Turkana could cause the salinity to rise to 3397 mg/L.[20] Raising salinity could also drastically reduce the number of fish in the lake, which the people around Lake Turkana depend on for sustenance and their livelihoods. According to critics, this "will condemn
8176-427: The lack of outflow, in ecology it is often regarded as a part of—or at least associated with—the Nile basin because of its prehistoric connection to this system and the similarities in their aquatic faunas . Due to temperature (its surface water typically is 27–31 °C [81–88 °F] and the mean air temperature of the region generally is similar or slightly higher), aridity and geographic inaccessibility,
8288-418: The lake retains its wild character. Nile crocodiles are found in great abundance on the flats. The rocky shores are home to scorpions and carpet vipers . The lake is rich in fish and fishing is very important to the local economy, but this is threatened by falling water levels and overfishing . Lake Turkana National Parks are now listed as a UNESCO World Heritage Site . Sibiloi National Park lies on
8400-418: The lake to a not-so-slow death."[9] According to dam proponents, the impact on Lake Turkana will be limited to the temporary reduction in flows during the filling of the reservoir. Various sources state that the filling could take between one and three wet seasons.[9][26] The total storage volume of the reservoir of Gibe III dam will be between 11.75 and 14 billion cubic meter, depending on sources. According to
8512-454: The lake's eastern shore, while Central Island National Park and South Island National Park lie in the lake. Both are known for their Nile crocodiles. An abundance of hominid fossils have been discovered in the area surrounding Lake Turkana. The area still sees few visitors, being two days' drive from Nairobi . The lake is also an imaginary boundary of the Rendille and Borana and Oromo to
8624-471: The lake, but migrate up the Omo River and other affluents to breed. The lake is heavily fished. The Lake Turkana region is home to hundreds of species of birds native to Kenya . The East African Rift System also serves as a flyway for migrating birds, bringing in hundreds more. The birds are essentially supported by plankton masses in the lake, which also feed the fish. Some birds more common to Turkana are
8736-409: The larger the crocodilian gets, the stronger its bite is likely to be. Therefore, a male saltwater crocodile, which had attained a length around 4.59 m (15 ft 1 in), was found to have the most powerful biting force ever tested in a lab setting for any type of animal. The Nile crocodile is the largest crocodilian in Africa, and is generally considered the second-largest crocodilian after
8848-569: The largest one being 68.6 cm (27.0 in) in length with a mandibular length of 87 cm (34 in). Nile crocodiles with skulls this size are likely to measure in the range of 5.4 to 5.6 m (17 ft 9 in to 18 ft 4 in), which is also the length of the animals according to the museum where they were found. However, larger skulls may exist, as this study largely focused on crocodilians from Asia. The detached head of an exceptionally large Nile crocodile (killed in 1968 and measuring 5.87 m (19 ft 3 in) in length)
8960-867: The latter region in eastern and southern Democratic Republic of Congo, and along the Central African coastal Atlantic region (as far north to Cameroon). Likely a level of habitat segregation occurs between the two species, but this remains to be confirmed. Nile crocodiles may be able to tolerate an extremely broad range of habitat types, including small brackish streams, fast-flowing rivers, swamps , dams, and tidal lakes and estuaries . In East Africa, they are found mostly in rivers, lakes, marshes , and dams, favoring open, broad bodies of water over smaller ones. They are often found in waters adjacent to various open habitats such as savanna or even semi-desert but can also acclimate to well-wooded swamps, extensively wooded riparian zones , waterways of other woodlands and
9072-542: The lion and the cheetah . Elephants and the black rhinoceroses are no longer seen, although Teleki reported seeing (and shooting) many. Closer to the dust is the cushioned gerbil ( Gerbillus pulvinatus ). Lake Turkana is an East African Rift feature. A rift is a weak place in the Earth's crust due to the separation of two tectonic plates , often accompanied by a graben , or trough, in which lake water can collect. The rift began when East Africa, impelled by currents in
9184-532: The local crocodiles have more osteoderms in their ventral surface than other known populations, and thus are of lesser value in leather trading, accounting for an exceptionally large (possibly overpopulated) local population there in the late 20th century. The segregation of the West African crocodile ( C. suchus ) from the Nile crocodile has been supported by morphological characteristics, studies of genetic materials and habitat preferences. The separation of
9296-399: The longest there being 3.65 m (12 ft 0 in). Crocodiles in aestivation are lethargic, entering a state similar to animals that hibernate . Only the largest individuals engaging in aestivation leave the burrow to sun on the warmest days; otherwise, these crocodiles rarely left their burrows. Aestivation has been recorded from May to August. Nile crocodiles usually dive for only
9408-422: The most common crocodilian in Africa. Among crocodilians today, only the saltwater crocodile occurs over a broader geographic area, although other species, especially the spectacled caiman ( Caiman crocodilus ) (due to its small size and extreme adaptability in habitat and flexibility in diet), seem to actually be more abundant. This species’ historic range, however, was even wider. They were found as far north as
9520-405: The muscular tendons used to shut the jaws are similar in proportional size. Only the gharial ( Gavialis gangeticus ) (and perhaps some of the few very thin-snouted crocodilians) is likely to have noticeably diminished bite force compared to other living species due to its exceptionally narrow, fragile snout. More or less, the size of the tendons used to impart bite force increases with body size and
9632-417: The only lake that retains the waters originating from two separate catchment areas of the Nile . The Lake Turkana drainage basin draws its waters mainly from Kenya Highlands and Ethiopian Highlands . The basement rocks of the region have been dated by two analytical determinations to 522 and 510 million years ago (mya). No rift was in the offing at that time. A rift is signalled by volcanic activity through
9744-819: The outcrops forming the rocky mountains and badlands around the lake. In the Omo portion of the basin, of the Mursi Basalts, the Mursi Formation is on the west side of the Omo, the Nkalabong on the Omo, and the Usno and Shungura east of the Omo. Probably the best known of the formations are the Koobi Fora on the east side of Turkana and the Nachukui on the west. Short-term fluctuations in lake level combined with periodic volcanic ash spewings over
9856-514: The perimeter of forests. In Madagascar, the remnant population of Nile crocodiles has adapted to living within caves. Nile crocodiles may make use of ephemeral watering holes on occasion. Although not a regular sea-going species as is the American crocodile , and especially the saltwater crocodile , the Nile crocodile possesses salt glands like all true crocodiles (i.e., excluding alligators and caimans), and does on occasion enter coastal and even marine waters . They have been known to enter
9968-478: The period when domesticated animals were first introduced to the region about 5000 years ago, while later, the dead were buried in small grave cairns. People who live in the region today commonly practice mixed subsistence, switching between hunting, fishing and animal herding based on what is feasible in a given year. However, the construction of infrastructure like Christian missionary stations, energy extraction (wind, oil) and NGO aid distribution points have made
10080-426: The presence of other animals. However, mouth-gaping (while essential to thermoregulation) may also serve as a threat display to other crocodiles. For example, some specimens have been observed mouth-gaping at night, when overheating is not a risk. In Lake Turkana , crocodiles rarely bask at all through the day, unlike crocodiles from most other areas, for unknown reasons, usually sitting motionless partially exposed at
10192-433: The primary subsistence economies. This was mostly supplanted by animal-based agriculture by 5000 years ago, when the lake level was in a period of rapid fluctuation. During the later Holocene , human responses to climatic changes included intensive fishing when lake level was high and a shift to cattle herding when the level dropped. Megalithic graves are found widely distributed on the lake shores and appear to correspond to
10304-451: The project did not assess the impact of the dam on the water level and water quality of Lake Turkana.[32] The director of Kenya's Water Services Regulatory Board, John Nyaoro, argued that the dam would have no negative impact on Lake Turkana.[33] A Kenya Government report in 2021 estimated that the surface area of Lake Turkana had increased by 10% between 2010 and 2020. Nile crocodile The Nile crocodile ( Crocodylus niloticus )
10416-494: The region have resulted in a fortuitous layering of the ground cover over the basal rocks. These horizons can be dated more precisely by chemical analysis of the tuff . As this region is believed to have been an evolutionary nest of hominins , the dates are important for generating a diachronic array of fossils, both hominoid and nonhominoid—that is, both ape (includes hominins) and non-ape . Many thousands have been excavated. Terraces representing ancient shores are visible in
10528-416: The region more connected to and dependent on outside resources for subsistence. Traditional modes of subsistence like pastoralism and fishing are now supplemented by the cash-based economy. The Lake Turkana Wind Power consortium (LTWP) plans to provide 310 MW of power to Kenya's national electricity grid by tapping the unique wind conditions around the lake. The plan calls for 365 wind turbines , each with
10640-426: The region's ethnic groups into cross-border violent conflict reaching well into South Sudan, as starvation confronts all of them. The report offers a devastating look at a deeply flawed development process fuelled by the special interests of global finance and African governments. In the process, it identifies major overlooked or otherwise minimised risks, not the least of which is a U.S. Geological Survey estimation of
10752-428: The saltwater crocodile and gharial reportedly both average around 4 m (13 ft 1 in), so are about 30 cm (12 in) longer on average, and the false gharial ( Tomistoma schlegelii ) may average about 3.75 m (12 ft 4 in), so may be slightly longer, as well. However, compared to the narrow-snouted, streamlined gharial and false gharial, the Nile crocodile is more robust and ranks second to
10864-403: The saltwater crocodile in total average body mass among living crocodilians, and is considered to be the second-largest extant reptile. The largest accurately measured male, shot near Mwanza, Tanzania, measured 6.45 m (21 ft 2 in) and weighed about 1,043–1,089 kg (2,300–2,400 lb). Another large male measuring 5.8 m (19 ft 0 in) in total length (Cott 1961)
10976-469: The sea in some areas, with one specimen having been recorded 11 km (6.8 mi) off St. Lucia Bay in 1917. Nile crocodiles have been recently captured in South Florida , though no signs that the population is reproducing in the wild have been found. Genetic studies of Nile crocodiles captured in the wild in Florida have revealed that the specimens are all closely related to each other, suggesting
11088-454: The shore of an ancient and larger Lake Turkana, and where numerous human skeletons showing major traumatic injuries to the head, neck, ribs, knees and hands are argued to be evidence of inter-group conflict between nomadic hunter-gatherers 10,000 years ago. With over 230 individuals found at the Koobi Fora site along the western shore, and scattered Homo sapiens skeletons with bone marks along
11200-510: The southern tip of Africa, may be smaller, reaching maximum lengths of only 4 m (13 ft 1 in). A crocodile population from Mali , the Sahara Desert , and elsewhere in West Africa reaches only 2 to 3 m (6 ft 7 in to 9 ft 10 in) in length, but it is now largely recognized as a separate species, the West African crocodile . The Nile crocodile is presently
11312-881: The surface in shallows, with no apparent ill effects from the lack of basking on land. In South Africa, Nile crocodiles are more easily observed in winter because of the extensive amount of time they spend basking at this time of year. More time is spent in water on overcast, rainy, or misty days. In the southern reaches of their range, as a response to dry, cool conditions that they cannot survive externally, crocodiles may dig and take refuge in tunnels and engage in aestivation . Pooley found in Royal Natal National Park that during aestivation, young crocodiles of 60 to 90 cm (24 to 35 in) total length would dig tunnels around 1.2 to 1.8 m (3 ft 11 in to 5 ft 11 in) in depth for most, with some tunnels measuring more than 2.7 m (8 ft 10 in),
11424-411: The tail and body. The underbelly of young crocodiles is yellowish green. As they mature, Nile crocodiles become darker and the cross-bands fade, especially those on the upper-body. A similar tendency in coloration change during maturation has been noted in most crocodile species. Most morphological attributes of Nile crocodiles are typical of crocodilians as a whole. Like all crocodilians, for example,
11536-471: The theories that they assist in digestion and staving off hunger. However, Alderton (1998) stated that a study using radiology found that gastroliths were seen to internally aid the grinding of food during digestion for a small Nile crocodile. Herodotus claimed that Nile crocodiles have a symbiotic relationship with a bird named the Trochilus which enter the crocodile's mouth and pick leeches feeding on
11648-452: The two is not recognized by the IUCN as their last evaluations of the group was in 2008 and 2009, years before the primary publications supporting the distinctiveness of the West African crocodiles. Although originally thought to be the same species as the West African crocodile , genetic studies using DNA sequencing have revealed that the Nile crocodile is actually more closely related to
11760-479: The use of duct tape to bind the jaws together. The broadest snouted modern crocodilians are alligators and larger caimans . For example, a 3.9 m (12 ft 10 in) black caiman ( Melanosuchus niger ) was found to have a notably broader and heavier skull than that of a Nile crocodile measuring 4.8 m (15 ft 9 in). However, despite their robust skulls, alligators and caimans appear to be proportionately equal in biting force to true crocodiles, as
11872-686: The weakened crust. The oldest volcanic activity of the region occurred in the Nabwal Hills northeast of Turkana and is dated to 34.8 mya in the late Eocene . The visible tectonic features of the region result from extensive extrusions of basalt over the Turkana-Omo basin in the window 4.18–3.99 mya. These are called the Gombe Group Basalts. They are subdivided into the Mursi Basalts and the Gombi Basalts. The two latter basalts are identified as
11984-456: Was Anam a Cheper . Natives who live around Lake Turkana include the Turkana , Rendille , Gabbra , Daasanach , Hamar Koke, Karo, Nyagatom, Mursi , Surma , and Molo peoples. For the location of many of these peoples, refer to the dialect map in the article. The lake was originally named Lake Rudolf (in honour of Crown Prince Rudolf of Austria ) by Count Sámuel Teleki de Szék and his second-in-command Lieutenant Ludwig Ritter Von Höhnel ,
12096-501: Was 5.5 m (18 ft 1 in) long weighed 905.7 kg (1,997 lb). On the other hand, another individual measuring 5.87 m (19 ft 3 in) in length was estimated to weigh between 770–820 kg (1,700–1,800 lb). In attempts to parse the mean male and female lengths across the species, the mean adult length was estimated to be reportedly 4 m (13 ft 1 in) in males, at which males would average about 280 kg (620 lb) in weight, while that of
12208-1191: Was among the largest Nile crocodiles ever recorded. It was estimated to weigh 1,082 kg (2,385 lb). Like all crocodiles, they are sexually dimorphic , with the males up to 30% larger than the females, though the difference is considerably less compared to some species, like the saltwater crocodile. Male Nile crocodiles are about 30 to 50 cm (12 to 20 in) longer on average at sexual maturity and grow more so than females after becoming sexually mature, especially expanding in bulk after exceeding 4 m (13 ft 1 in) in length. Adult male Nile crocodiles usually range in length from 3.3 to 5.0 m (10 ft 10 in to 16 ft 5 in) long; at these lengths, an average sized male may weigh from 150 to 750 kg (330 to 1,650 lb). Very old, mature ones can grow to 5.5 m (18 ft 1 in) or more in length (all specimens over 5.5 m (18 ft 1 in) from 1900 onward are cataloged later). Large mature males can reach 1,000 kg (2,200 lb) or more in weight. Mature female Nile crocodiles typically measure 2.2 to 3.8 m (7 ft 3 in to 12 ft 6 in), at which lengths
12320-410: Was found to have weighed 166 kg (366 lb), including the large tendons used to shut the jaw. The bite force exerted by an adult Nile crocodile has been shown by Brady Barr to measure 22 kN (5,000 lbf). However, the muscles responsible for opening the mouth are exceptionally weak, allowing a person to easily hold them shut, and even larger crocodiles can be brought under control by
12432-464: Was proposed in 1986 by V. P. Alexeev. In 1984, the Turkana Boy , a nearly complete skeleton of a Homo ergaster juvenile, was discovered by Kamoya Kimeu . More recently, Meave Leakey discovered a 3.5 million-year-old skull there, designated Kenyanthropus platyops ("the flat-faced man of Kenya"). Marta Mirazón Lahr discovered early evidence of human warfare at the site of Nataruk , located near
12544-400: Was thought to be the closest relative of the Nile crocodile, but more recent research has indicated that Rimasuchus , despite its very large size (about 20–30% bigger than a Nile crocodile with a skull length estimated up to 97 cm (38 in)), is more closely related to the dwarf crocodile ( Osteolaemus tetraspis ) among living species. Two other fossil species from Africa retained in
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