Description
For many centuries, the Nile crocodile has brought fear and horror to all living organisms living near it. Mentions of this reptile date back to the existence of Ancient Egypt, and there are also hypotheses that crocodiles lived back in the time of dinosaurs.
Today, the population of Nile crocodile individuals in the world numbers 250-500 thousand individuals and is included in the Red List of Threatened Species as a taxon of minimal risk (LC). In the 1940s - 1960s, the extermination of Nile crocodiles for the sake of their skin led to a sharp decline in the population, and only thanks to national and international measures taken, the extinction of the species was stopped. However, despite all efforts, cases of poaching are not uncommon. In addition, the lack of education and knowledge of proper behavior among the natives of the species’ habitats leads to the extermination of individuals that threaten the lives of careless people and domestic animals.
The Nile crocodile is one of the most large reptiles, which reaches a length of 5-6 meters together with the tail. However, depending on the habitat, certain characteristics of the species are distinguished, including in size. Average weight an adult weighs 600-800 kg with a length of 4-5 meters. Individuals whose length reaches 6 meters or more weigh about 1000 kg.
The body structure of the Nile crocodile allows the species to be perfectly adapted to hunting in aquatic environment. The reptile's tail is long and powerful, which helps it swim quickly and, pushing off from the bottom of the reservoir, quickly jump to distances significantly exceeding the size of the reptile itself. The body of the Nile crocodile is flattened, short hind legs are equipped with wide membranes, and the jaws are long and powerful. The skin of the Nile crocodile, unlike most of its relatives, is quite smooth without ridges and covered with scales. There are 4-6 scutes on the back of the head; the dorsal scutes are separated from the occipital scutes and placed in equal rows. The organs of vision, breathing and hearing are located on the top of the crocodile's head, which allows it to dive under water, hiding from prey, and at the same time observe the surroundings. Crocodylus niloticus has 64-68 teeth, 36-38 of which are maxillary, 28-30 are mandibular.
The color of young individuals is greenish with bright black spots on the sides, on the back and a straw-yellow hue on the belly and throat. With age, the color fades and becomes darker from olive to dark green on the sides, on the back, and the belly and throat acquire a dirty yellow tint.
In addition to all of the above, the skin of the Nile crocodile is equipped with highly sensitive receptors that respond to the slightest vibrations in the water. The reptile sees perfectly not only during the day, but also at night. But at the same time, the Nile crocodile’s hearing and sense of smell are much better developed than its vision.
The three-chambered heart saturates the reptile's blood well with oxygen, which allows, if necessary, to remain under water for up to two hours with reduced activity. Usually, the Nile crocodile takes in enough air into its lungs to stay on the surface of the water and releases it in order to quickly dive into the depths. A crocodile dives for an average of 2-3 minutes. When a crocodile dives underwater, its ears close, as do its nostrils. The eyes are closed with a membrane (the so-called third eyelid), which protects them from exposure to water and at the same time allows them to see. In addition, to wash the mucous membrane, there are glands around the crocodile’s eyes, which were the basis for the aphorism “crocodile tears.”
The Nile crocodile is able to open its mouth in water thanks to a leathery growth that is located at the back of the throat and blocks the access of water to the respiratory system.
The metabolism of Crocodylus niloticus, like that of most cold-blooded animals, is quite slow, which allows it to go tens of days without food. But at the same time, a hungry crocodile is able to eat up to half its own weight at a time.
Crocodile dimorphism is expressed only in primary sexual characteristics and the size of individuals - males usually exceed females in size. Therefore, determine the sex of a crocodile by external signs impossible.
IN wildlife The lifespan of Nile crocodiles can reach 60-70 years.
Origin and habitats in nature
The species Crocodylus niloticus belongs to the genus Crocodylus (True crocodiles) of the family Crocodylidae (Crocodiles). Unofficially, several subspecies are recognized, DNA analysis of some of which has shown differences, indicating possible genetic differences among populations. However, to date, this fact has not been fully studied, and it is possible to talk only about existing differences in the size of individuals, which may be due to the habitat.
In countries with cool climates, the size of an adult individual averages 4 m (South African Nile crocodile), while in Mali and the Sahara Desert, the size of adult individuals does not reach more than 2-3 m in length, due to which they were called Dwarf Nile crocodiles.
The habitat of the species Crocodylus niloticus extends across almost all of Africa, in the Nile River basin, sub-Saharan Africa, as well as in Morocco, Mauritius, Sao Tome and Principe, Cape Verde, Zanzibar, Socotra Island and Madagascar. Judging by the fossil remains, this species previously lived much further north - in Algeria, Libya, Lebanon, Syria, Palestine, Jordan, the Comoros Islands and was recently exterminated in Israel. In addition, a small population of the species also lives in Palestine today, but in a single place - the Crocodile River.
The habitat biotope is limited to freshwater or slightly brackish lakes, rivers, swamps, and river mouths. It can be noted that the Nile crocodile prefers to live in more or less calm water, with a sandy coastal zone. It is extremely rare to spot a Nile crocodile at a great distance from a body of water. And this may be connected with the search for a new habitat due to the drying up of the reservoir in the previous one.
Lifestyle
The Nile crocodile cannot be called a herd animal, but they live in large groups and often hunt in groups. At the same time, a strict hierarchy is observed in each group, which does not lead to conflicts. The largest individuals always dominate in groups.
But group hunting does not take place so often; more often individuals lead single image life. At dawn, the Nile crocodile comes out onto the coastal sand and dries in the sun, while its mouth is usually open at this moment. Having warmed up in the sun, the crocodile returns to the pond to hunt around noon. Since the Nile crocodile can eat quite a lot, it hunts almost every day, but in those cases when it is not hungry, then at lunch it can either simply swim around the perimeter of its area or remain on coastal zone half asleep. It is impossible to say that a crocodile ever completely falls asleep, since thanks to its sense of touch, it always feels everything that happens around it.
When a group of crocodiles is resting on the same beach, the dominant (i.e. larger) individuals are always in the most convenient places, and the distance between each crocodile is quite respectful. At sunset, the Nile crocodile always returns to the pond for hunting, which continues throughout the night and early morning. Thus, individuals of the Nile crocodile are predominantly nocturnal.
Nile crocodiles most often hunt for fish, but often swamp and water birds, small and large mammals that come to the pond where the crocodile lives to drink become prey. The Nile crocodile waits for its prey, completely immersed in the water and leaving only its eyes, nose and ears on the surface. It is capable of completely silently and imperceptibly swimming up to its prey at a sufficient distance, and then, in a sharp jump, grab the prey by the throat and also quickly drag it under water.
Underwater, a crocodile either strangles its prey or waits for it to choke. There have been cases when crocodiles left their prey under water for some time, placing it between the roots of trees, or in crevices so that the meat softened.
If the prey managed to avoid the attack of the crocodile, then it will not pursue it on land. It was extremely rare for crocodiles to rise more than halfway out of the reservoir while feeding. Crocodiles will also not hunt on the shore. Crocodiles can eat prey that is already dead, but they avoid meat in which the process of rotting has already begun.
The crocodile most often kills the fish with blows of its tail, after which it swallows it. When hunting in groups, several crocodiles herd fish into schools, where they have the opportunity to stun more prey. In this case, the larger individuals swallow the prey first, and their small relatives can only collect the remains of the dominant individuals.
Acoustic communication between individuals consists of a fairly extensive set of sound signals. Sounds always accompany mating tournaments. In addition, a characteristic dull moo can be heard when an individual is restless. An angry crocodile makes sounds similar to hissing sniffles. Young, newly hatched individuals make loud croaking sounds.
In general, the behavior of the Nile crocodile can be characterized as individual and social. He can manifest himself both in groups and alone. There is even a certain semblance of intelligence in it, and therefore cunning moves during the hunt are possible, as well as the ability to guard and protect the offspring, which is not typical of most other reptiles.
The Nile crocodile has the reputation of a cannibal, because due to carelessness, according to information from various sources, several hundred people become victims of crocodiles every year in their habitats. However, there are no official statistics to confirm or deny this information impossible.
When deciding to keep a Nile crocodile in captivity, a person must understand the full extent of responsibility towards this animal and his loved ones who may be near him. In the presence of a crocodile, a person should never be careless, because first of all, the Nile crocodile is a dangerous predator, possessing enormous strength, lightning-fast reaction, as well as all the qualities inherent in it by nature, intended for successful hunting. A crocodile will never become tame, and therefore you need to treat it with caution, without being deceived by its apparent indifference.
Terrarium: Taking into account the significant size of the Crocodylus niloticus species, it is necessary to prepare a spacious terrarium. Even a young individual needs a fairly large space, because they grow quite quickly, and a small terrarium can last no more than 1-2 years. Therefore, it is better to prepare a terrarium with an adult in mind.
For the Nile crocodile, it is recommended to prepare large swimming pool where he can swim freely. The size of the pool should be at least twice the size of the reptile in length and at least a minimum margin for turning around. In a 1:1 ratio with the reservoir, the aquaterrarium should have an island of land, above which a heating point should be organized.
The water level in the pool should be at least half a meter. The water in the terrarium must be fresh and free of harmful impurities, such as chlorine. In addition, it is advisable to make the reservoir flowing and install a sufficient number of filters. The water should always be clean; partial replacement is recommended 1-2 times a week. A complete change of water in the pool must be done at least once a month.
Substrate: the most optimal view The substrate on land will be coarse gravel with sand, which, if necessary, can be washed and dried. It is necessary to place several large and medium-sized stones and driftwood in the water. Access to land should be comfortable and gentle.
Content temperature: The Nile crocodile is a heat-loving tropical animal, and therefore the temperature should be no less than +34°C during the day and no lower than +24°C at night. The water temperature should be maintained at +28 - +30°C. The warming up point must be organized in one corner of the terrarium so that the crocodile can control its own body temperature.
Lighting: During the day, the terrarium should be well lit. In addition, a prerequisite for the successful absorption of minerals important for the crocodile’s body is the presence of an ultraviolet radiation lamp. It is necessary to monitor the circadian rhythm and arrange the lighting in such a way that there is a period of twilight twice a day.
Decor: to create partial shade in the terrarium, you can plant unpretentious tropical plants - they will also decorate the space, but for crocodiles the presence of vegetation is not a necessary condition.
Feeding in captivity
It is necessary to feed Nile crocodiles in captivity as close as possible to their diet in the natural environment. So the menu of young animals can be composed large insects, baby frogs, newborn mice. Adults can be fed with rats, live fish, and unplucked chicken. It has been noted that after eating fish, crocodiles easily switch to eating meat, but if you feed them only meat for a fairly long period, they may refuse fish. But this phenomenon is temporary and, after being a little capricious, the pet will eat fish.
Pre-killed prey, pieces of meat or thawed fish are suitable for feeding captive bred individuals that have been conditioned to consume such food. But even in this case, the volume of live prey should prevail.
Feeding intervals for adults can be 4-6 days, while young animals need to be fed every other day. Volume of food to be taken adult per week should be 5% of body weight, and for young animals - 10%.
Vitamin supplements in the form of calcium and others important elements, which make up vitamin complexes for reptiles, must be given once a week to young animals and once a month to adults.
Breeding
At good conditions When kept, Nile crocodile individuals become sexually mature at approximately 8-10 years of age, when their body size reaches 3 m for males and 2-2.5 m for females.
The mating season begins with male tournaments, which the female watches and gives preference to the largest male. Roars, snorting, head slapping in the water - this is far from full list ways in which males try to attract the attention of a female during the mating season. During mating games, the resulting pairs rub the undersides of their muzzles and make various sounds.
The mating season begins during the dry season. Mating occurs in water and lasts 1-2 minutes. About 60 days after mating, the female begins to dig a hole, about 50 cm deep on land, in the sand. Often in the wild, several females dig burrows close to each other and jointly guard the clutches.
One clutch consists of 40-60 eggs. After laying eggs, the female fills the nest with rotting vegetation, which in the process of decay creates additional heat, which contributes to better incubation of the eggs, and also camouflages the nests from predators. Despite the fact that females, and sometimes males, very jealously guard the clutches, they are often subjected to devastation by other predators. But most common cause The death of the clutch is caused by early rains, which flood nests located close to water bodies.
The incubation period averages 80-90 days. The sex of the cubs is determined by incubation temperature. Young animals have a small growth (egg tooth) in the nose area, thanks to which they can peck an egg. When pecking at an egg, small crocodiles begin to make ringing sounds, which are a signal for the female, after which she opens the nest and often, together with the male, helps the young to get out of the egg, widening the crack in it with her tongue, and then carries them to the water.
Couples protect their cubs until they are 2 years old, after which they drive them away from their area. Then the young ones wander alone along the reservoirs, trying not to catch the eye of adults who may feast on the young animals. Having reached sexual maturity, young crocodiles return to their native shore.
When breeding Nile crocodiles in captivity, it is necessary to place a sufficient amount of vegetation in the terrarium and prepare a place with a substrate in the form of a mixture of moss, peat and shavings. The substrate must be sufficiently hygroscopic, since embryos receive moisture not only from the air, but also from the soil.
In order for sexually mature individuals to pay attention to each other, it is recommended to keep the female separately until the mating season. If you place a female with two mature males, then skirmishes will begin, during which the animals can seriously injure each other.
The incubation temperature should be +30 - +32°C. There must be water under the substrate in which the eggs are located to create conditions as close as possible to incubation in the wild.
The Nile crocodile (lat. Crocodylus niloticus) is a large reptile animal from the order of crocodiles, the family of crocodilians, the genus of these.
The Nile crocodile is the most common member of the family, the largest African crocodile and the second largest giant reptile in the world, second only in size to the saltwater crocodile.
The main food of an adult Nile crocodile is various small and large mammals: cane rats, otters, bush cats, civets, . Various species (waterbucks, impalas, kudu, gazelles), large forest aards, aardvarks, African manatees, as well as all types of domestic animals that accidentally wander into a watering hole become large prey. The largest Nile crocodiles attack buffaloes, cubs and, brown hyenas and big cats.
Nile crocodiles also eat carrion, steal food from hyena dogs, etc. The predatory reptile has a slow metabolism, so the animal can starve for a long time, but when happy hunting the volume of food consumed at a time can be up to 20% of its own weight, and crocodiles feed at every opportunity. Only female Nile crocodiles, guarding their nests, eat little.
Reproduction of Nile crocodiles.
Sexual maturity of Nile crocodiles occurs at 12-15 years of age, when males grow to 2.5-3 m, and females up to 2-2.5 m in length. The onset of mating season depends on the habitat: Northern part The population breeds in the summer, and individuals living in the south breed during the rainy season - in November and December.
During the rut, special, hierarchical relationships are established among sexually mature males of the Nile crocodile. Quite aggressive clashes often occur between representatives of the species, in which males demonstrate their superiority over their opponent. Crocodiles exhale noisily through their mouths, make growling or grumbling-like sounds, and blow bubbles with their open mouths. Simultaneously with these demonstration actions, Nile crocodiles, excited by the fight for the future female, bend their necks, raise their tails, whipping them on the surface of the water. Having admitted defeat, one of the males turns around and swims away at high speed, trying to escape the pursuit of a competitor. If it is not possible to escape, the losing crocodile raises its head high, opening access to its throat: this position is a sign of peace and recognition of defeat. The winning crocodile sometimes grabs one of the opponent's limbs with its jaws, but does not bite it. Such “prenuptial” fights make it possible to expel extra males from the territory favored by a pair of crocodiles.
During the breeding season, males behave quite unusually and interestingly: they roar invitingly, snort loudly, slap their muzzles in the water and try in every possible way to attract females, with females preferring the largest males. Mating games consist of singing peculiar trills, during which the partners open their mouths wide and rub the lower surfaces of their muzzles.
The place for laying eggs becomes sandy beaches and shallows, dry beds and river banks. Near the water's edge, the female Nile crocodile digs a nest up to 60 cm deep and lays 20 to 95 eggs (usually around 55-60). The female vigilantly guards the buried clutch throughout the entire incubation period, which is approximately 90 days. Periodically, the male helps her, and the couple fights back against anyone who poses a threat to the offspring. Occasionally, the female is forced to hide from the heat, and the Nile crocodile's nest left unattended is destroyed by mongooses, spotted hyenas, baboons and people. Sometimes nests built in the wrong place suffer from floods. In total, only 10-15% of eggs survive to the end of incubation.
Newborn crocodiles make grunting sounds, which becomes a signal for the female: she digs up the nest, and sometimes parents even help the cubs to be born by rolling the egg between the tongue and the palate. The mother accompanies the hatched offspring to the pond or carries it in her mouth.
The sex of Nile crocodile cubs, like any other crocodiles, is formed under the influence of the temperature inside the nest during the second month of incubation: at temperatures from 31.7 to 34.5 degrees, males are born, in other cases females. The length of newborn Nile crocodiles is approximately 28 cm, but in the first year of life the cubs develop quite quickly. By the end of the first year, crocodiles grow up to 60 cm in length, by two years - up to 90 cm. For two years, the female takes care of her offspring, sometimes together with other females, establishing something like a “nursery”, after which the grown individuals are about 1 .2 m leave their mother and, until puberty, avoid meeting with major representatives kind.
Young crocodiles dig holes up to 3.6 meters long in the banks, which serve as shelter for them until they are 5 years old. Adults also dig similar burrows for themselves under the roots of trees hanging over the water.
The most ancient animal, living since the time of dinosaurs, is the crocodile. The most dangerous species are the Nile and saltwater crocodile. It is these animals that account for the largest number of human casualties.
In this article we will talk about the Nile crocodile.
It is found throughout the Seychelles and Comoros Islands, Madagascar. Relatively recently, it could still be found in Asia, but today it is completely exterminated there. Nile crocodiles divided into a large number of types:
These are found in rivers and freshwater. They can reach a length of 4 to 6 meters, but giants with a length of 7 meters are also known. These animals can weigh from 270 to 910 kg.
From the photographs it can be seen that Nile crocodiles do not have a very long muzzle, which does not exceed its width. Young animals are brown and also dark olive in color. An adult crocodile is dark green in color with black spots on its back, and its belly is lighter than the rest of the animal's body, often a dirty yellow color. With age, the reptile becomes more and more pale.
The nostrils and eyes of crocodiles are located at the top of the head, which is why they can breathe and see when the rest of the body is in the water. Unlike other animals, these reptiles have external ears that close like the nostrils when crocodiles dive.
The Nile crocodile is a diurnal animal. During the night they lie down in bodies of water, and when the sun rises, they go hunting, or continue to rest in the sun.
Nutrition and hunting of the Nile crocodile
The Nile crocodile eats quite varied. Small reptiles feed on, for example, dragonflies. More large crocodiles– shellfish, fish, and crustaceans. Sometimes their prey is a bird, a reptile, or a mammal such as a rhinoceros or buffalo. Sometimes animals attack lions and tigers.
The reptile waits for its future victim in the water, near the shore. It may take more than one hour until something living approaches the water. Then the reptile swims closer to the prey and waits at a distance of about several meters, at which time its body is immersed in water, with the exception of its eyes and nostrils. Suddenly, the reptile jumps out of the water and grabs the victim's head with its mouth, drowning it, dragging it into deep water. Then, with the help of its powerful jaws, the crocodile tears out parts of the meat.
When hunting fish, the reptile hits its tail to stun and frighten it, and the one that is stunned is swallowed. Reptiles feed quite often, although they can go without food for several days, sometimes for a year or even more.
Crocodiles are remarkably adapted to living underwater and in the water. They use their paddle-like, powerful tail to swim. The hind legs are webbed. Another adaptation to aquatic life is the presence of a third eyelid: a membrane that, when immersed under water, protects its eyes, while the crocodile can see further. Crocodiles can stay under water for a very long time: on average, about forty minutes, and older crocodiles may not surface for more than one hour.
Of course, on land reptiles are slower than in water, but they still develop a fairly good speed of 30 km/h. But the most interesting thing is that on land crocodiles are very cowardly and do everything possible to run away to the water as quickly as possible. It is for this reason that only about 3 out of 10 reptile attacks occur on land.
Reproduction of Nile crocodiles
Crocodiles become ready to reproduce only at 8-12 years of age. A female individual lays 50 eggs. Throughout the entire incubation period, a period of 80-90 days, she remains close to the nest, then provides assistance to the newborns in getting out of the nest. Young crocodiles live with their mother for two years.
Plan
Introduction
1 Description
1.1 Appearance
1.2 Physiology
1.3 Dimensions
2 Reproduction
3 Food
4 Distribution and protection
5 Nile crocodile as an object of sport hunting
6 Cult of the Nile crocodile
7 Classification
Bibliography Introduction
Nile crocodile (lat. Crocodylus niloticus) is a large reptile of the family of true crocodiles. The largest of the 3 species of crocodiles found in Africa, and the second largest in the world after the saltwater crocodile. Due to its habitat, size and strength, it is known as a man-eating crocodile and was an object of fear and worship in ancient times. To this day it remains perhaps the most known species crocodiles. In general, the species' numbers are relatively high and stable, although populations in some countries are endangered. 1. Description
1.1. Appearance
Like all crocodiles, the Nile crocodile has short legs located on the sides of the body, scaly skin covered with rows of bony plates, a long strong tail and powerful jaws. The crocodile's eyes are equipped with a third eyelid. additional protection and have special glands that allow them to be washed with tears (hence the expression “ crocodile tears"). The nostrils, ears and eyes are located at the top of the head, thanks to which the crocodile can almost completely submerge in water, leaving them on the surface. The coloring of the Nile crocodile also allows it to remain undetected. Juveniles are usually gray or light brown with dark stripes on the back and tail. With age, the color darkens and the stripes become less noticeable. The belly has a yellow tint; this skin is considered to be of the highest quality. Usually the crocodile crawls on its stomach, but can also walk with its body raised. Small individuals are able to run a short distance at a gallop, developing a speed of 12-14 km/h. It also swims quickly (30 km/h), making sinusoidal movements with its tail. 1.2. Physiology
The heart is four-chambered, like a bird’s, which allows it to oxygenate the blood more efficiently. Typically, the Nile crocodile dives for 2-3 minutes, but if necessary can remain under water for up to 30 minutes, and with reduced activity - up to two hours. Being a cold-blooded animal, it has a relatively slow metabolism and can go without food for a long time, but at the same time it is able to eat up to half its body weight in one sitting. The Nile crocodile has fairly good hearing and a rich vocal range. Its skin is equipped with special receptors that respond to changes in water pressure. The jaws have impressive strength, which allows them to hold large animals. Typically has 64-68 conical teeth - 36-38 on the upper jaw and 28-30 on the lower jaw. Newly hatched crocodiles have a special tooth-like seal of skin at the front of their snout that helps them escape from the egg. 1.3. Dimensions
The Nile crocodile is large in size, usually about 5 m, occasionally up to 5.5 m. Weight often exceeds 500 kg, and there are individual specimens weighing over 1200 kg. The largest known specimen was killed in Tanzania in 1905: length 6.45 m, weight 1090 kg. Reports of 7-meter crocodiles have not been confirmed. On southern border range - in South Africa, Nile crocodiles are somewhat smaller in size, their length usually does not exceed 4 m. Like other species of crocodiles, they exhibit sexual dimorphism - females are on average 30% smaller than males. In general, the differences are smaller than in many other species. Crocodiles living in colder climates, such as southern Africa, are smaller - about 4 m. The dwarf Nile crocodile, living in Mali and the Sahara Desert, grows only to 2 -3 m. It is believed that such differences in size are a consequence of worse living conditions, and not genetic differences. 2. Reproduction
Under normal conditions, the Nile crocodile becomes sexually mature by the age of ten, when it reaches a length of 3 m for males, 2-2.5 m for females. During the mating season, males attract females by slapping the water with their snouts, roaring, snorting and making other noises. Large males are usually more attractive to females. During mating games, couples “sing” peculiar trills and rub the undersides of their muzzles. The time of egg laying largely depends on latitude - in the north of the range it occurs during the dry season, and in the south it is usually tied to the beginning of the rainy season - November or December. In Zimbabwe, females lay eggs in September or early October. Favorite places for building nests are sandy beaches, dry riverbeds and river banks. The female digs a hole up to 50 cm deep two meters from the shore and lays from 20 to 85 eggs (50 on average). Several females can build nests close to each other. After laying the eggs, the expectant mother covers the nest with sand and guards it during the 3-month incubation period. The father is usually nearby too, and both parents will attack anyone who tries to approach the nest. Despite such care, many nests are destroyed by people, monitor lizards and other animals if the mother leaves to hide from the heat or take a dip in the water. The hatched cubs make chirping sounds, and at this signal the mother breaks the nest. Parents sometimes take the eggs into their mouths and squeeze them between the tongue and roof of the mouth to help the offspring release. The female then leads the crocodiles to the water or carries them in her mouth. As with other crocodiles, the sex of the young is determined by temperature during the middle third of the incubation period, rather than genetically. If the temperature inside the nest was below 31.7 °C or above 34.5 °C, then females are born, otherwise - males. Newly hatched crocodiles are about 30 cm long and grow quite quickly in the first years. The mother takes care of the offspring for two years. If several nests were close to each other, mothers can jointly care for their offspring, forming a kind of crocodile nursery. Within two years, young crocodiles reach a size of 1.2 m and leave their native places, while avoiding the territories of older and larger crocodiles. Average duration The lifespan of Nile crocodiles is 45 years; there are specimens up to 80 years old. 3. Food
Newly hatched crocodiles feed on insects and aquatic invertebrates, quickly switching to amphibians, reptiles and birds. The diet of even adult crocodiles consists of 70% fish and other small vertebrates, despite the fact that a crocodile can eat almost any animal that comes to a watering hole, with the exception of adult elephants and hippos. The Nile crocodile also readily eats carrion, although it avoids rotten meat. A group of crocodiles can travel hundreds of meters from the shore to reach the carcass of a large animal. An adult crocodile uses its body and tail to push a school of fish towards the shore, and grabs it with a quick movement of its head. Crocodiles can also form a group and block migrating fish by forming a semicircle across the river. In this case, dominant crocodiles eat first. It is known that Nile crocodiles can successfully attack zebras, antelopes, buffalos, young hippos and rhinoceroses, giraffes, warthogs, hyenas, monkeys, felines, as well as other crocodiles. The ability to almost completely hide under water, combined with high speed over short distances, makes crocodiles good hunters of large prey. They capture her powerful jaws, pulled into the water and kept there until she drowned. When the prey is dead, they tear off pieces of it and swallow it. When sharing joint prey, they coordinate efforts to tear the body apart, and can also push it under snags or stones for this purpose. The Nile crocodile poses a danger to people, although to a lesser extent than the saltwater crocodile. Females are especially dangerous during the period of caring for offspring, when they become especially aggressive towards any animal approaching the nest. Most attacks occur far from civilization and are not recorded, so the actual number of victims is unknown. According to some sources, it is 1000 people a year, according to others - 200. In 2005, a crocodile was caught in Uganda, which, according to local residents, ate 83 people in 20 years. In 2006, Richard Root, a professor of medicine at the University of Washington, fell victim to a crocodile in Botswana. It is believed that the Nile crocodile has a symbiotic relationship with some birds, such as the clawed lapwing ( Vanellus spinosus). According to some reports, the crocodile opens its mouth wide, and at this time the bird takes out pieces of meat stuck in its teeth. However, these reports have proven difficult to verify, and it may not be a truly symbiotic relationship. 4. Distribution and protection
The Nile crocodile prefers to live along the banks of rivers and lakes and in freshwater swamps, and is sometimes found in brackish water, estuaries or mangroves. It is distributed throughout almost all of sub-Saharan Africa, as well as in Madagascar and the Nile Basin. It once lived much further north - fossil remains of this animal were discovered in Algeria, Israel and Jordan, as well as on the Comoros Islands. From the 1940s to the 1960s, the Nile crocodile was heavily hunted, mainly for its high-quality skin, less so for its meat and the supposed medicinal properties of its organs. This led to a multiple reduction in the number of the species, resulting in the threat of its extinction. The Nile crocodile is widespread in many countries of southern and eastern Africa, such as Somalia, Ethiopia, Kenya, Zambia, the population size is monitored and documented. The Nile crocodile is listed as “Red” list" of the World Conservation Union for the category of minimal risk. The crocodile trade is regulated international convention according to Appendix I of CITES. 5. Nile crocodile as an object of sport hunting
In many countries where stable populations of Nile crocodiles remain, hunting for them is allowed under quotas. The main way to hunt a crocodile is to lie in wait near the bait. For bait, as a rule, highly rotten pieces of meat or a whole carcass of a small animal (antelope, goat, baboon, etc.) are used, which are placed so that the crocodile gets out of the water when it gets to the meat. At some distance from the bait, a hiding spot is set up - usually a grass hut. Crocodiles show extreme caution, so the hut is placed at a distance of 70-80 meters from the bait. Crocodiles are good at noticing extraneous sounds; in addition, they can pay attention to unusual behavior birds that see a person. This requires the hunter to be able to sit in ambush completely quietly and unnoticed. Unlike many other predators, the crocodile is active in relation to the bait at any time of the day. Shooting is carried out only at a crocodile that has crawled ashore. Hunting a Nile crocodile requires a fairly powerful weapon (caliber, for example, .300 Win Mag or even .375 H&H Magnum), but in addition, the weapon must have high accuracy and shooting accuracy. The killing points of a crocodile are extremely small - small areas on the head and neck. Hitting requires high precision due to the fact that the crocodile must be placed immediately on the spot and not allowed to go into the water - a killed crocodile always drowns, but it is extremely difficult to pull it out. 6. Cult of the Nile crocodile
The people of Ancient Egypt worshiped the god Sobek, who was associated with fertility, protection and the power of the pharaoh. The attitude towards him was ambivalent: sometimes they hunted crocodiles and insulted Sebek, sometimes they saw him as a protector and source of power for the pharaoh. Sebek was compared with the earth god Geb, the solar deity Ra and Osiris. Sebek was depicted as a crocodile, a crocodile mummy, or a man with the head of a crocodile. The center of his cult in the Middle Kingdom was the city of Shedit, which the Greeks called Crocodilopolis, and even later Arsinoe. Another large temple of Sebek was located in the city of Kom Ombo, and many smaller ones were in many other cities of Egypt, mainly in Upper Egypt and the Nile Delta. Herodotus wrote that in the 5th century BC. e. some Egyptians kept crocodiles as pets. In the pool of the temple of Sebek in Arsinoe lived a crocodile, where he was fed, decorated with jewels and worshiped. When he died, his body was mummified, placed in a sarcophagus and buried in a tomb. A number of mummified crocodiles and crocodile eggs were indeed found in ancient Egyptian graves. Several well-preserved mummies are in the Cairo Museum. In order to calm the crocodiles, Ancient Egypt special spells were used. Even in modern Nubia, fishermen hang a figurine of a crocodile over the threshold of their house to protect themselves from evil. The worship of the Nile crocodile is also common among many other peoples of Africa. In some areas of Burkina Faso, the Nile crocodile is a sacred animal. According to the religious beliefs of the Mosi people, more than half of whose representatives live in this country, every person has a soul in the form of an animal - a snake, an antelope, a hare or a crocodile. To kill this animal on the territory of the village means to kill the person whose soul has its appearance. 7. Classification
Depending on the region of residence and external features There are several subspecies of the Nile crocodile.
- Crocodylus niloticus africanus(East African Nile crocodile) Crocodylus niloticus chamses(West African Nile crocodile) Crocodylus niloticus corviei(South African Nile crocodile) Crocodylus niloticus madagascariensis(Malagasy Nile crocodile) Crocodylus niloticus niloticus(Ethiopian Nile crocodile) Crocodylus niloticus pauciscutatus(Kenyan Nile crocodile) Crocodylus niloticus suchus(Central African Nile crocodile)
- Allen E. Greer. On the Maximum Total Length of the Salt-Water Crocodile (Crocodylus porosus) // Journal of Herpetology. - 1974. - T. 8. - No. 4. Jamie Richard Oaks. Phylogenetic systematics, biogeography, and evolutionary ecology of the true crocodiles (Eusuchia: Crocodylidae: Crocodylus) // M.S. thesis, Louisiana State University. - 2007. Nile crocodile. Encyclopedia Britannica. Encyclopedia Britannica, Inc. David Quammen. Monster of God: The Man-eating Predator in the Jungles of History and the Mind. - United States: W. W. Norton & Company, 2000. - pp. 127-129. - 515 s. - ISBN 0393326098 Hunt Crocodiles With Bullet Safaris (English). Bullet Safaris. Amira El-Noshokaty. Lord of the Nile (English) Al-Ahram Weekly. Species of crocodilians (English). Science Encyclopedia. N. S. Flint, F. H. van der Bank, J. P. Grobler. A lack of genetic variation in commercially bred nile crocodiles (Crocodylus niloticus) in the North-West Province of South Africa // Water S.A.. - 2000. - T. 26. - No. 1. Adam Britton Do crocodiles cry "crocodile tears"? (English). Crocodilian Biology Database. Florida Museum of Natural History. Adam Britton Crocodylus niloticus (Laurenti, 1768) (English). Crocodilian Species. Florida Museum of Natural History. Crocodile (English). Botswana Tourism Board. Myths and facts from The Chamber of Horrors of Travel Medicine, PDF. (English) Nile Crocodile (English). Crocodilian Species. Gorongosa National Park. Amélie L. Vergne, Alexis Avril, Samuel Martin, Nicolas Mathevon. Parent–offspring communication in the Nile crocodile Crocodylus niloticus: do newborns’ calls show an individual signature? // Naturwissenschaften. - 2007. - T. 94. - No. 1. - P. 49-54. A. Aulie, T. I. Kanui. Oxygen consumption of eggs and hatchlings of the. Nile crocodile (Crocodylus. niloticus) // Comparative biochemistry and physiology. - 1995. - T. 112. - No. 1. - P. 99-102. Denis Charles Deeming. Reptilian Incubation: Environment, Evolution and Behavior. - Nottingham: Nottingham University Press, 2004. - 349 p. - ISBN 1897676115 Nonindigenous Aquatic Species Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0-85112-235-9 Crocodilian Species - Nile Crocodile (Crocodylus niloticus) (English) S. V. Mezhzherin. Relationship between genetic variability and body size in vertebrates // Genetics. - 2002. - T. 38. - No. 9. Nile crocodile. Animal bytes. seaworld.org. C.A.W. Guggisberg. Crocodiles. - David & Charles PLC, 1972. - P. 195. - 200 p. - ISBN 0715352725 Christopher P. Kofron. Courtship and mating of the Nile crocodile (Crocodylus niloticus) // Amphibia-Reptilia. - 1991. - T. 12. - No. 1. Christopher P. Kofron. Nesting ecology of the Nile crocodile (Crocodylus niloticus) // African Journal of Ecology. - 2008. - T. 27. - No. 4. - P. 335-341. NILE CROCODILE: Temperature Dependent Sex Determination - Pulse of the Planet Africa’s Most Dangerous Animals - The Top 7 (English) Tom Paulson Top UW doctor killed by crocodile in Africa. Seattle Post-Intelligencer. Alvin Silverstein, Laura Silverstein Nunn. Symbiosis. - 21st Century, 1998. - 64 p. - ISBN 0761330011 Crocodylus niloticus. Species Accounts. Florida Museum of Natural History.. World Conservation Union Red List (English) CITES, Appendix I (English) Nile Crocodile Trade (English). Hunt Crocodiles With Bullet Safaris. Bullet Safaris (2008). Crocodile Hunting (English). AfricaHunting.com. (1) Fetishism and totemism. Animal cult Geraldine Harris, Delia Pemberton. Illustrated Encyclopedia of Ancient Egypt. - Peter Bedrick Books, 2001. - pp. 142-143. - 160 s. - ISBN 0872266060 Herodotus. Book two. Euterpe. // History (in 9 books). - M.: Eksmo, Midgard, 2008. - 704 p. - ISBN 978-5-699-29702-3 Sacred Nile Crocodile Mummies. Animal Mummy Project. Cairo Egyptian Museum. Carol Andrews, Carol Andrews Raymond Oliver Faulkner, Raymond Oliver Faulkner. The Ancient Egyptian Book of the Dead. - Austin: University of Texas Press, 1972. - 192 p. - ISBN 0292704259 Richard Bangs. Richard Bangs" Adventures with Purpose: Dispatches from the Front Lines of Ear. - Birmingham: Menasha Ridge Press, 2007. - 346 pp. - ISBN 0897327365 Richard Ferguson. Keynote Paper on Human-Wildlife Conflicts for the 16th meeting of FAO African Forest & Wildlife Commission // IUCN SSC Crocodile Specialist Group. - 2008. Christopher D. Roy The Art of Burkina Faso. The University of Iowa. http://odub.ukg.kz/new%20for%20site/ref/cro.doc The Reptile Database: Crocodylus niloticus(English)
Titles: Nile crocodile.
Given the wide distribution range of the Nile crocodile, several varieties have evolved that are rarely mentioned in the literature and none of the varieties are officially recognized as subspecies status:
- East African Nile crocodile - Crocodylus niloticus africanus;
- West African Nile crocodile - Crocodylus niloticus chamses;
- South African Nile crocodile - Crocodylus niloticus corviei;
- Malagasy Nile crocodile - Crocodylus niloticus madagascariensis;
- Ethiopian Nile crocodile - Crocodylus niloticus niloticus;
- Kenyan Nile crocodile - Crocodylus niloticus pauciscutatus;
- Central African Nile crocodile - Crocodylus niloticus suchus.
Area: Distributed throughout Africa, except its northern part, in Madagascar, Comoros and Seychelles. In ancient times it lived in Egypt and Palestine, but nowadays it is not found below the second cataract on the Nile. In South-West Asia (in the Tserka River, Israel), the Nile crocodile was exterminated quite recently. The species was registered in the following countries African continent: Angola, Benin, Botswana, Burundi, Cameroon, Central African Republic, Chad, Congo, Egypt, Ethiopia, Equatorial Guinea, Gabon, Gambia, Ghana, Guinea, Ivory Coast - Ivory Coast, Kenya, Liberia, Madagascar , Malawi, Mali, Mozambique, Mauritania, Namibia, Niger, Nigeria, Rwanda, Senegal, Sierra Leone (West Africa), Somalia, South Africa, Sudan, Swaziland, Tanzania, Togo, Uganda, Zaire, Zambia, Zimbabwe.
Description: In the Nile crocodile, the length of the muzzle does not exceed its width at the base by more than twice. 4-6 occipital scutes are arranged in one transverse row and 4 large occipital scutes form a square, the first transverse row of which is bordered on the sides by two smaller scutes. The dorsal scutes are rectangular, oriented in regular longitudinal and transverse rows; the dorsal scutes of the middle pair of longitudinal rows do not differ from the other dorsal scutes. The skin of crocodiles, unlike other crocodiles, grows with them, so crocodiles do not shed. Crocodiles' eyes and nostrils are located at the top of their head, so they can see and breathe while the rest of their body is submerged. Unlike other reptiles, they have external ears that close, as do the nostrils, when crocodiles dive. Another adaptation to life in water is the third eyelid, a membrane that covers the eyes when submerged, thus protecting the crocodile's eyes from exposure to water without losing the ability to see. It is impossible to determine the sex of a crocodile by appearance. The male has a penis, but it is removed only during the mating season. All crocodiles have a leathery growth at the back of the throat that blocks water from entering the respiratory organs when the animal is underwater. This allows you to keep your mouth open underwater without the risk of choking. Crocodiles swallow small stones, which settle in their stomach and help grind their food. According to some researchers, the pebbles in the crocodile's stomach serve as ballast. The total number of teeth is 64-68.
Color: Juvenile Nile crocodiles are dark olive and brown in color with a black cross pattern on the body and tail. In adults, the pattern fades and becomes paler
Size: The Nile crocodile reaches a length of up to 5 meters (some reports say up to 6 meters). There is evidence that Nile crocodiles living in southern Africa (in countries with cooler climates) reach smaller sizes - up to 4 meters. There are two species of dwarf Nile crocodiles, found in Malawi and the Sahara Desert. Because of unfavorable conditions, these varieties reach sizes of 2-3 meters.
The cubs that have just hatched from the eggs are about 28 cm long, by the end of the first year of life they reach 60 cm, by two years - 90 cm, at 5 years - 1.7 m, at 10 years - 2.3 m and at 20 years - 3.75 m.
Weight: 272-910 kg.
Lifespan: More than 50 years.
Voice: The Nile crocodile is capable of emitting a cry similar to a dull moo. He screams only when he is very excited. Young crocodiles, recently hatched from eggs, make a peculiar croaking sound, reminiscent of the cheerful chatter of frogs.
Habitat: Inhabits a wide variety of bodies of water: lakes, rivers, freshwater swamps, bodies of brackish water. Most often it settles outside forest areas, but also enters forest reservoirs.
Enemies: Young Nile crocodiles can be attacked by goliath herons, marabou, . There are known cases of death of quite large crocodiles from. For adult crocodiles, the main enemy is humans.Food: The food of the Nile crocodile is very varied and changes with age. Teenagers feed on small aquatic animals and, as they grow, large vertebrates are added to the diet. Individuals about 2.5 m long feed on mollusks, and even larger ones feed on fish, reptiles, and mammals. Adult Nile crocodiles can attack such large mammals like buffalos and even though fish and small vertebrates make up most their diet. 
Behavior: Nile crocodiles spend the night in the water, and by sunrise they come out to the shallows and bask in sun rays. The midday, hottest hours are spent in the water, with the exception of cloudy days. In windy, inclement weather, animals spend the night on the shore. The maximum duration of stay under water for crocodiles up to 1 m in length is about 40 minutes; larger individuals can stay under water much longer. Crocodiles swim using their powerful paddle-like tail. Only the hind feet are webbed, but they are rarely used when moving underwater. On land, the crocodile moves on short, seemingly weak legs. When walking, it places its paws close to its body and rises above the ground. Sometimes they move at a gallop, like. At the same time, they rely on their front paws, and carry their hind paws beyond their front paws, transfer the weight of the body onto them and then throw their hind paws forward. The speed that Nile crocodiles can reach while galloping is 29 US miles per hour. Adult individuals can migrate far from habitats when they grow to 1.2 meters. An adult crocodile, as a rule, does not move away from the water and only when its pond dries up does it rush in search of a new home. At this time, many crocodiles die without reaching their goal.
When hunting for fish, the crocodile beats with its tail in order to frighten and stun it; it swallows the stunned fish. Sometimes crocodiles cooperate to hunt, for example, one crocodile blocks off an area of water so that the concentration of fish in it increases.
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