Nile crocodile - Wikipedia. The Nile crocodile (Crocodylus niloticus) is an African crocodile and may be considered the second largest extantreptile in the world, after the saltwater crocodile (Crocodylus porosus). The range of this species once stretched northward throughout the Nile, as far north as the Nile delta. On average, the adult male Nile crocodile is between 3. They are generalists, taking a variety of prey. The Nile crocodile is an ambush predator that 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 an extremely powerful bite that is unique amongst all animals and sharp conical teeth that sink into flesh allowing for a grip that is almost impossible to loosen. They can apply high levels of force for extended periods of time, a great advantage for holding down large prey underwater to drown. There is a strict hierarchy, which is determined by size. Large, old males are at the top of this hierarchy and have primary 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. The hatchlings are also protected for a period of time, but hunt by themselves and are not fed by the parents. It is a rather common species of crocodile and is not endangered despite some regional declines or extinctions. Etymology. The Nile crocodile is called tanin ha- yeor in Hebrew. It also sometimes referred to as the African crocodile, Ethiopian crocodile, common crocodile or the black crocodile. These have consisted of: C. The Nile crocodile apparently is more closely related to the crocodiles of the Americas, namely the American (Crocodylus acutus), Cuban (Crocodylus rhombifer), Morelet's (Crocodylus moreletii) and Orinoco crocodile (Crocodylus intermedius), than to the West African crocodile or other extant African crocodilians. There is some variation 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.
As it matures, the Nile crocodiles becomes darker and the cross- bands fade, especially those on the upper- body. A similar tendency is coloration change during maturation has been noted in most crocodile species. Like all crocodilians, for example, 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. The species, however, also has small oval osteoderms on the sides of the body as well as the throat. The nostrils, eyes, and ears are situated on the top of the head, so the rest of the body can remain concealed underwater. Levels of lactic acid as high as they are in a crocodile would kill most vertebrates. The spectacled caiman is the most widely distributed New World crocodilian, ranging from Mexico in the north to Peru and Brazil in the south. Caiman crocodilus.The American alligator (Alligator mississippiensis), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile endemic to the. 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. For most of a crocodile's life, broken teeth can be replaced. On each side of the mouth, there are five teeth in the front of the upper jaw (premaxilla), 1. The enlarged 4th lower tooth fits into the socket on the upper jaw and is visible when the jaws are closed, as is the case with all true crocodiles. Among crocodilians, the Nile Crocodile possesses a relatively long snout, which is approximately 1. Nile crocodiles with skulls this size are likely to measure in the range of 5. However, larger skulls may exist as this study largely focused on crocodilians from Asia. Brady Barr to measure 5,0. N). However, the muscles responsible for opening the mouth are exceptionally weak, allowing a person to easily hold them shut with a small amount of force or to use duct- tape to adhere the jaws together even in large crocodiles. For example, a 3. Melanosuchus niger) was found to have skull that was notably broader and heavier than that of a Nile crocodile measuring 4. 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 the larger the crocodilian gets, the stronger its bite is likely to be. Therefore, a very large male saltwater crocodile, which had attained a length of approximately 4. The largest accurately measured male, shot near Mwanza, Tanzania, measured 6. Male Nile crocodiles are about 3. A smaller population from Mali, the Sahara Desert and elsewhere in West Africa reaches only 2 to 3 m (6 ft 7 in to 9 ft 1. Among crocodilians today, only the saltwater crocodile occurs over a broader geographic area. They were found as far north as the Mediterranean coast in the Nile delta and across the Red Sea in Israel 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. Additionally, the Nile crocodile is known from fossil remains to have once inhabited Lake Edward on the border between the Democratic Republic of the Congo and Uganda. They are thought to have become extinct in the Seychelles in the early 1. They have occasionally been spotted in Zanzibar and the Comoros in modern times but occur very rarely. In Madagascar, the remnant population of Nile crocodiles has adapted to living within caves. In comparison, the slender- snouted crocodile (Mecistops cataphractus) tends to occupy rivers within forest interiors, while dwarf crocodiles are distributed in smaller rivers (mainly tributaries), streams and brooks also within forested areas. Lucia Bay in 1. 91. It is unknown how many Nile crocodiles are currently at large in Florida. More than half of the crocodiles observed by Cott (1. If their jaws are bound together in the extreme midday heat, Nile crocodiles may easily die from overheating. More time is spent in water in overcast, rainy or misty days. Crocodiles in aestivation are totally lethargic, entering a state similar to animals who hibernate. Only the largest individuals engaging in aestivation would leave the burrow to sun on warmest days, otherwise these crocodiles rarely left their burrows. Aestivation has been recorded from the months of May to August. Nile crocodiles normally crawl along on their bellies, but they can also . Smaller specimens can gallop, and even larger individuals are capable on occasion of surprising bursts of speed, briefly reaching up to 1. Although it has been made quite clear that this is a deliberate behaviour for the species, the purpose is not definitively known. Gastroliths are not present in hatchling aged crocodiles, but increase quickly in presence within most crocodiles examined at 2–3. One crocodile measuring 3. Cott (1. 96. 1) felt that gastroliths were most likely serving as ballast to provide stability and additional weight to sink in water, this bearing great probability over the theories that they assist in digestion and staving off hunger. In the water, this species is an agile and rapid hunter relying on both movement and pressure sensors to catch any prey unfortunate enough to present itself inside or near the waterfront. However, for such large animals, their stomachs are relatively small, not much larger than a basketball in an average- sized adult, so as a rule they are anything but voracious eaters. In general, at the smallest sizes (0. Nile crocodiles were most likely to have full stomachs (1. Cott); adults at 3–4 m (9 ft 1. Interestingly, in the largest size range studied by Cott, 4–5 m (1. For example, in Lake Turkana, Kenya, 4. Occasionally, a crocodile quietly surfaces so that only its eyes (to check positioning) and nostrils are visible, and swims quietly and stealthily towards its mark. The attack is sudden and unpredictable. The crocodile lunges its body out of water in practically the blink of an eye and grasps its prey. On other occasions, more of its head and upper body is visible, especially when the terrestrial prey animal is on higher ground, to get a sense of the direction of the prey item as the top of an embankment or on a tree branch. The immense bite force, which may be as high as 5,0. N) in large adults, ensures that the prey item can't escape through the grip. 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 up into pieces with the help of other crocodiles. Some crocodiles of the species may habitually use their tails to sweep terrestrial prey off- balance, sometimes forcing the prey specimen into the water where it can be more easily drowned. Their ability to lie concealed with most of their bodies underwater, combined with their speed over short distances, makes them effective opportunistic hunters of larger prey. They grab such prey in their powerful jaws, drag it into the water, and hold it underneath until it drowns. They will also scavenge or steal kills from other predators, such as lions and leopards (Panthera pardus). 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. When groups are sharing a kill, they use each other for leverage, biting down hard and then twisting their bodies to tear off large pieces of meat in a . They may also get the necessary leverage by lodging their prey under branches or stones, before rolling and ripping.
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