Which animal. These communal nesting sites are not known to exist today, perhaps being most recently recorded at Ntoroko peninsula, Uganda where two such sites remaining until 1952. [77] Much prey taken is much smaller than the crocodile itself and such prey can be overpowered and swallowed with ease. Both sexes can be very territorial as well as aggressive in nature during this period of time. (2002). Its place in the ecosystems it inhabits is largely unique, as it is the only large tetrapod carnivore that spends the majority of its life in water and hunting prey associated with aquatic zones. 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. Retrieved on 2013-04-25. [65] Genetic studies of Nile crocodiles captured in the wild in Florida have revealed that the specimens are all closely related to each other, suggesting a single source of the introduction. [94] Additionally, crocodiles readily take dead or dying fish given the opportunity, thus are likely to incidentally improve the health of some fish species’ populations as this lessens their exposure to diseases and infection. [2] Although capable of living in saline environments, this species is rarely found in saltwater, but occasionally inhabits deltas and brackish lakes. (2002). [10] 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 the surface in shallows with no apparent ill effect from the lack of basking on land. (2008). [27][29] 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. Incautious human behavior is the primary drive behind crocodile attacks. [85], Larger fish, like catfish and freshwater bass, are preferred by adults more than 2.2 m (7 ft 3 in) in length. [18] The segregation of the West African crocodile (C. suchus) from the Nile crocodile has been supported by morphological characteristics,[17][19] studies of genetic materials[16][19] and habitat preferences. [3][49] The full range of causes for mortality of young Nile crocodiles is not well understood, as very young and small Nile crocodiles or well-concealed nests are only sporadically observed. [7] The colouration also helps to camouflage it; juveniles are grey, multicoloured, or brown, with dark cross-bands on the tail and body. [3][153] Nile crocodiles have temperature-dependent sex determination (TSD), which means the sex of their hatchlings is determined not by genetics as is the case in mammals and birds, but by the average temperature during the middle third of their incubation period. 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. Receive information about animals, environment, nature and our planet. Among the larger males of a population, territorial clashes can lead to physical fighting between males especially if they are near the same size. Does anyone know????????? [42][7] In one case, a crocodile was filmed capturing a striated heron (Butorides striata) in mid-flight. The crocodile lunges its body out of water in practically the blink of an eye and grasps its prey. [7][155] The female may micturate sporadically on the soil to keep it moist, which prevents soil from hardening excessively. [3][10] The Nile crocodile is one of the most dangerous species of crocodile and is responsible for hundreds of human deaths every year. [25][26], Adult Nile crocodiles have 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. Preferred nesting locations are sandy shores, dry stream beds, or riverbanks. In the Zambezi River and Lake St. Lucia, Nile crocodiles have been known to prey on bull sharks (Carcharhinus leucas) and sand tiger sharks (Carcharias taurus). [20] The separation of the two is not recognized by the IUCN as their last evaluations of the group was in 2008 and 2009,[1][21] years before the primary publications supporting the distinction of the West African crocodiles. [11], In studies preceding the slaughter of crocodiles for the leather trade, when there were believed to be many more Nile crocodiles, a roughly estimated 1,000 human fatalities per annum by Nile crocodiles were posited with a roughly equal number of aborted attacks. [3][6][49] 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 the female is 3.05 m (10 ft 0 in), at which females would average about 116 kg (256 lb). Alderton, D. (1998). [8][18], The mouths of Nile crocodiles are filled with 64 to 68 sharply pointed, cone-shaped teeth (about a dozen less than alligators have). Just a guess. [187][188][189] Other wild animals responsible for more annual human mortalities either attack humans in self-defense, as do venomous snakes,[190] or are deadly only as vectors of disease or infection, such as snails,[191] rats[192] and mosquitos. [3][7][115] Cape porcupines (Hystrix africaeaustralis) are known to have been preyed on several times in Kruger National Park, their quills apparently being an insufficient defense against the tough jaws and digestive systems of crocodiles. [33][34] 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. Outside water, crocodiles can meet competition from other dominant savannah predators, notably big cats, which in Africa are represented by lions, cheetahs, and leopards. [49][150][152] In the Olifants River in South Africa, rainfall influenced the size of nesting females as only larger females (greater than 3 m (9 ft 10 in)) nested during the driest years. [3][7][166], Conservation organizations have determined that the main threats to Nile crocodiles, in turn, are loss of habitat, pollution, hunting, and human activities such as accidental entanglement in fishing nets. [82][83], After Nile crocodiles reach 2 m (6 ft 7 in), the significance of most invertebrates in the diet decreases precipitously. [39] However, despite their robust skulls, alligators and caimans appear to be proportionately equal in biting force to true crocodiles, as the muscular tendons used to shut the jaws are similar in proportional size. [3][64], Nile crocodiles are an invasive species in North America, and several specimens have been recently captured in South Florida, though no signs that the population is reproducing in the wild have been found. They were found as far north as the Mediterranean coast in the Nile Delta and across the Red Sea in Israel and Syria. Large mammalian predators in Africa are often social animals and obligated to feed almost exclusively on terrestrial zones. In Kruger National Park, over the course of 22 years of discontinuous observation, 60% of the large-game kills observed as perpetrated by crocodiles consisted of impala, while more than 15% of observed kills were made up of waterbuck (Kobus ellipsiprymnus), the largest of the genus Kobus at more than 200 kg (440 lb) in weight. As cold-blooded creatures, Nile crocodiles need to eat far less compared to an equivalent-weighted warm-blooded animal. [3][27][28] According to the Guinness Book of World Records, the typical mature size is between 3.4 and 3.7 m (11 ft 2 in and 12 ft 2 in), while Alexander and Marais (2007) state it is 2.8 to 3.5 m (9 ft 2 in to 11 ft 6 in) and Garrick and Lang (1977) claim from 3.0 to 4.5 m (9 ft 10 in to 14 ft 9 in). [3][157][158][159] The behaviour of the female Nile crocodile is considered unpredictable and may be driven by the regional extent of prior human disturbance and human persecution rather than natural variability. If the temperatures are very warm they will hatch sooner. However, Cott (1961) found that the only size range where fish were numerically dominant over other types of food was from 2 to 3.05 m (6 ft 7 in to 10 ft 0 in). In Florida", "Introduction of Nile Crocodiles in southern Florida", "Nile crocodiles captured in South Florida still have scientists seeking answers", "An experimental and morphometric test of the relationship between vertebral morphology and joint stiffness in Nile crocodiles (, "Croc Blog: Crocodile myths #1 – the curious trochilus", "Nile Crocodile: Photos, Video, E-card, Map – National Geographic Kids". 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.

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