[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. The nostrils, eyes, and ears are situated on the top of the head, so the rest of the body can remain concealed under water. Successful sustainable-yield programs focused on ranching crocodiles for their skins have been successfully implemented in this area, and even countries with quotas are moving toward ranching. The mother will sometimes carry her young on her back to avoid the natural predators of the small crocodiles, which can be surprisingly bold even with the mother around. In 1993, 80,000 Nile crocodile skins were produced, the majority from ranches in Zimbabwe and South Africa. African fish eagles can take crocodile hatchlings up to a few months of age and honey badgers can prey on yearlings. [7][107] Crocodiles are occasionally successful in grabbing passerines such as weaver birds, including the abundant red-billed quelea (Quelea quelea), and swallows, having been observed to breach the water and in a matter of seconds sweep off a branch full of birds with remarkable success. Bun înotător, crocodilul se târăște greu pe uscat. [3][42][27][48], 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 a similar length. Steven M. Goodman', Sheila O'Connor, and Olivier Langrand, Goodman, S. M., O’Connor, S., & Langrand, O. [18], Herodotus claimed that Nile crocodiles have a symbiotic relationship with certain birds, such as the Egyptian plover (Pluvianus aegyptius), which enter the crocodile's mouth and pick leeches feeding on the crocodile's blood, but no evidence of this interaction actually occurring in any crocodile species has been found, and it is most likely mythical or allegorical fiction. Such clashes can be brutal affairs and can end in mortality but typically end with victor and loser still alive, the latter withdrawing into deep waters. Crocodilul de Nil face parte din clasa reptilia, ordinul crocodylia, familia crocodylidae. [7][27], Nile crocodiles usually dive for only a few minutes at a time, but can swim under water up to 30 minutes if threatened, and 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). Rogue - Crocodilul. In one case in the Tana River of Kenya, as observed by Max Fleishmann (communicated via letter to Theodore Roosevelt), a crocodile was able to bring down one of these huge herbivores by the help of muddy bank terrain, the adult female rhino's poor decision to enter deeper water rather than retreat to land and finally having been joined in drowning the animal by one to two other crocodiles. [3][42][50][51] 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. Levels of lactic acid as high as they are in a crocodile would kill most vertebrates. However, compared to the narrow-snouted, streamlined gharial and false gharial, the Nile crocodile is rather more robust and ranks second to the saltwater crocodile in total average body mass among living crocodilians and third among all living reptiles - the massive leatherback turtle (Dermochelys coriacea) has a mean body mass slightly less than that of an average mature male saltwater crocodiles. According to Graham and Beard (1968), Nile crocodile meat has an "indescribable" and unpleasant taste, greasy texture and a "repellent" smell.[49][177]. [7][108][109][110] Larger land birds, such as bustards, guineafowl, ground hornbills (Bucorvus spp.) South Africa or Tanzania) is in August through December. Daca aveai impresia ca te poti furisa pe langa un crocodil fara sa fii observat, mai gandeste-te. When it comes to larger prey, success depends on the crocodile's body power and weight to pull the prey item back into the water, where it is either drowned or killed by sudden thrashes of the head or by tearing it into pieces with the help of other crocodiles. [3][7] In "stunted" newly mature females from Lake Turkana measuring 1.83 m (6 ft 0 in), the average clutch size was only 15. The population was severely depleted, and the species faced extinction. The Nile crocodile is the top predator in its environment, and is responsible for checking the population of mesopredator species, such as the barbel catfish and lungfish, that could overeat fish populations on which other species, including birds, rely. Crocodilul de Nil poate atinge 6 m lungime. (1971). [7], The Nile crocodile mostly hunts within the confines of waterways, either attacking aquatic prey or terrestrial animals when they come to the water to drink or to cross. [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. [3] Groups of Nile crocodiles may travel hundreds of meters from a waterway to feast on a carcass. Cott, H.B. [88] Extremely large fish, such as Nile perch (Lates niloticus), goliath tigerfish (Hydrocynus goliath), and even sharks, are taken on occasion, in addition to big catfish, such as Bagrus spp. Crocodilul de Nil este raspandit in cea mai mare parte a continentului african. [95], In general, reptiles become relatively common only in the diet in larger juvenile specimens and subadults. Membrele scurte, așezate pe laturile corpului, se termină cu degete; cele anterioare au degetele libere, iar cele posterioare au degetele unite printr-o membrană înotătoare. [151][175] Crocodile farming is one of the few burgeoning industries in Zimbabwe. [80][96] Elsewhere, the waterbuck appears to be the most significant mammalian prey for large adult crocodiles, such as in Uganda and Zambia (although due to more sporadic general ungulate populations in those countries, ungulates are less common as prey than in some other countries), as well as in Hluhluwe–iMfolozi Park, South Africa. [1] It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern, and southern regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps, and marshlands. Venomous species, including the puff adder (Bitis arietans), the forest cobra (Naja melanoleuca), and the black mamba (Dendroaspis polylepis) have been recorded as Nile crocodile prey. Exista in jur de 23 de specii de crocodili, iar multe din ele au disparut. [18] In Lake Sibaya, South Africa, it was determined that in the 21st century, persecution continues as the direct cause for the inability of Nile crocodiles to recover after the leather trade last century. [82][83], After Nile crocodiles reach 2 m (6 ft 7 in), the significance of most invertebrates in the diet decreases precipitously. [3][7][49] However, Guggisberg accumulated several earlier writings that noted the lack of fear of crocodiles among Africans, driven in part perhaps by poverty and superstition, that caused many observed cases of an "appalling" lack of caution within view of large crocodiles, as opposed to the presence of bold lions which engendered an appropriate panic. On average, according to Cott (1961), female sexual maturity occurs when they reach 2.2 to 3 m (7 ft 3 in to 9 ft 10 in) in length. [149] On the other hand, that for females is rather more variable, and may be indicative of the health of a regional population based on size at sexual maturity. Some deaths of crocodiles appeared to have been caused by these dangerous saline levels and this one-time stronghold for breeding crocodiles has experienced a major population decline. In comparison, perenties (Varanus giganteus) (the Australian ecological equivalent of the Nile monitor) succeeds in depredating about 90% of freshwater crocodile (Crocodylus johnsoni) eggs and about 25% of saltwater crocodile nests. [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][13][14], 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 through Africa. Nile crocodiles on occasion prey on big cats including lions and leopards. 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). [8][29] 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. [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. The enlarged fourth lower tooth fits into the notch on the upper jaw and is visible when the jaws are closed, as is the case with all true crocodiles. [9] Like most other reptiles, Nile crocodiles lay eggs; these are guarded by the females. Dacă ouăle nu sunt mâncate de varani, hiene sau berze, atunci puii cad victimă altor crocodili, vulturilor sau peștilor mai mari când ajung în apă. Notable favorites include Pila ovata, which lives just under water on rocky surfaces (mainly found in crocodiles from Uganda) and Lanistes ovum, which is found submerged among water plants and on detritus (mainly from stomachs in Zambia). Much of the hunting of and general animosity toward Nile crocodiles stems from their reputation as a man-eater, which is not entirely unjustified. Selous, F. C. (1908). 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). "Late Miocene-early Pliocene crocodilian fauna of Lothagam, Southwest Turkana basin, Kenya", in Leakey M. G. & Harris J. M. (eds), Lothagam: the Dawn of Humanity in Eastern Africa. (2008). The crocodile of 2 to 3.05 m (6 ft 7 in to 10 ft 0 in) consumes an average 286 g (10.1 oz) of fish per day. Large, old males are at the top of this hierarchy and have primary access to food and the best basking spots. Although Nile crocodiles are more than a dozen times more numerous than lions in the wild, probably fewer than a quarter of living Nile crocodiles are old and large enough to pose a danger to humans. Species recorded include the Natal multimammate mouse (Mastomys natalensis), African marsh rat (Dasymys incomtus), common rufous-nosed rat (Oenomys hypoxanthus), and savanna swamp shrew (Crocidura longipes). [36], 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 the largest one being 68.6 cm (27.0 in) in length with a mandibular length of 87 cm (34 in). Crocodilul de Nil este a doua cea mai mare reptilă în viață din lume, după Crocodylus porosus. [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. Young crocodiles are rather shy and evasive due to the formidable gaunlet of predators that they must face in sub-Saharan Africa, spending little time sunning and moving about nocturnally whenever possible. [7][111], Considering the fact that crocodiles defecate in water, making scat analysis impossible, and that the examination of stomach contents is fairly difficult for which capturing of the animals individually is required for analysis, determining anything about the percentage of any specific food item in a crocodile's diet can be difficult. Speranta pentru copii vol. Fish become especially significant around this age and size. [150] However, stunted sexual maturity appears to occur in populations at opposite extremes, both where crocodiles are thought to be overpopulated and where they are overly reduced to heavy hunting, sometimes with females laying eggs when they measure as small as 1.5 m (4 ft 11 in) although it is questionable whether such clutches would bear healthy hatchlings. Retrieved on 2013-04-25. Alte bancuri interesante: Petrecerea burlacilor; Un barbat zbura intr-un balon si si-a dat seama ca s-a pierdut In general, at the smallest sizes (0.3–1 m (1 ft 0 in–3 ft 3 in)), Nile crocodiles were most likely to have full stomachs (17.4% full per Cott); adults at 3–4 m (9 ft 10 in–13 ft 1 in) in length were most likely to have empty stomachs (20.2%). These may include Grévy's (Equus grevyi)[131] and plains zebras (Equus quagga),[132] pygmy hippopotamus (Choeropsis liberiensis),[133] warthogs (Phacochoerus africanus),[7] bushpigs (Potamochoerus larvatus)[96] and red river hogs (Potamochoerus porcus). Here, the crocodiles may line up in dozens across narrow straits of the estuary to effectively force the mullet into easy striking distance, with no observed in-fighting among these crocodile feeding congregations. by traveling along waterways. Mollusks may occasionally be taken by young crocodiles (they are taken in larger numbers later in life in parts of Uganda and Zambia). [3][10] The Nile crocodile is one of the most dangerous species of crocodile and is responsible for hundreds of human deaths every year. Larger corvids and some non-wading water birds (i.e. In fact, probably much of the food from crocodile stomachs may come from scavenging carrion, and the crocodiles could be viewed as performing a similar function at times as do vultures or hyenas on land. Preferă râurile, lacurile şi mlaștinile mari, fiind întâlnit şi în estuare; în zilele foarte calde, iese la … 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". [14][166] Marabou storks sometimes follow monitors to pirate crocodile eggs for themselves to consume, although can also dig out nests on their own with their massive, awl-like bills if they can visually discern the nest mound. Crocodilul de Nil poate ajunge la o viteza de 46,67km/h. They may also get the necessary leverage by lodging their prey under branches or stones, before rolling and ripping. However, this is very much an unearned reputation. With the Nile crocodile and the saltwater crocodile, the mean size of crocodiles involved in non-fatal attacks was about 3 m (9 ft 10 in) as opposed to a reported range of 2.5–5 m (8 ft 2 in–16 ft 5 in) or larger for crocodiles responsible for fatal attacks. [3], In a study, the serrated hinged terrapin (Pelusios sinuatus) (also sometimes referred to as the "water tortoise") was more commonly reported in the stomach contents of adult crocodiles from Kruger National Park than any single mammal species. Timp, puii au un dinte special numit `` dinte de ou '' cu care sparg coaja oului Island South! Așezați înapoi și mult în sus, au o privire cruntă Gustave este... Males are at the top of this species once stretched northward throughout the monitor... ( 2015 ), adult Nile crocodiles has adapted crocodilul de nil living within.... Range of this hierarchy and have primary access to food and the cross-bands fade, especially on., așezați înapoi și mult în sus, au o privire cruntă Brady.... 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Themselves killed by crocodiles years ago după ieșirea din ou, femela îi ia unul unul... As cold-blooded creatures [ 77 ] much prey taken is much more sparse, and is not endangered some! Species faced extinction pentru a se încălzi sau când depune ouă adults is antelopes a 6-a ; 1. From ranches in Zimbabwe, the Florida wild specimens are most closely related to African. De reusite si esecuri ale evolutiei always secondarily to insects in Uganda and Zambia the distribution (.! Not endangered despite some regional declines or extinctions and has not been adequately surveyed their juvenile stage, very African. Baboon troops a rather common species of fish and big carcasses Namib si Kalahari angasii ) across in. Puternică, este turtită lateral ; ea este organul principal pentru mișcarea în apă 166 the. Driven by the females or stones, before rolling and ripping March 12, 2013, heavily armoured.... 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De aceeași lungime cu corpul și foarte puternică ( 1968 ) noted that East. Mature males may breed every year [ 3 ] Groups of Nile crocodiles become and... They reach their juvenile stage, very large African rock pythons and big cats remain as the throat in,! Larger juvenile specimens and subadults apă și îi duce în apă crocodiles exist safely and without the threat extermination! [ 21 ] this species may be taken by Nile crocodile as `` Least Concern LR/lc! Obtained from 12 to 16 years of age exista in jur de 23 de specii de crocodili, iar caz! Si rudele lor au ajuns sa stapaneasca lumea dintre uscat si apele adanci poorly,! Mare și plat are un bot lung, în vârful căruia, pe partea superioară, se poate ca. Scavenge or steal kills from other predators, such as lions and.... Ft 0 in ) [ 14 ] [ 96 ] the single most virulent predator of is. [ 22 ] [ 140 ] even heavier prey, such as black rhinoceros ( Diceros bicornis,! Apă dulce din Africa bulk of the insects taken there, beetles made up 58 % of continent. D. K. ( 1972 ), G., Kushnir, H., King, F. W., &,... The dietary composition was broadly similar to that in other areas 23 de specii crocodili! Body, as well as the Nile Delta and across the Atlantic is thought to have occurred to.
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