What types of crocodiles exist. What a crocodile eats

CROCODILE
  CROCODILE squad  (Crocodylia) is a family of reptiles. Three species live in Africa. The narrow-crocodile is endemic to Africa. It dwells in all major rivers of West Africa, Lake Tanganyika and in the east of the mainland. Stray (or dwarf) crocodile - in central Africa. Nile crocodile - on the mainland and some islands.

Crocodiles hold a special position among modern reptiles, being closer relatives of extinct dinosaurs, which they survived by almost 60 million years, and modern birds, than other reptiles of our time. A number of features of the organization of crocodiles, and above all the perfection of the nervous, circulatory and respiratory systems, suggests that they are the most highly organized of all living reptiles. The evolution of crocodiles, beginning with the emergence of this group about 150 million years ago, has been moving in the direction of an increasing adaptation to aquatic life and predation. The fact that crocodiles have survived to our time is often explained by their life in various freshwater reservoirs of the tropical and subtropical belts, that is, in places whose conditions have changed little since the appearance of crocodiles.

The overall shape of the body, a crocodile lizard. They are characterized by a long, laterally compressed, high tail, membranes between the fingers of the hind limbs, a long muzzle and a flattened head in the dorsal-ventral direction. There are five fingers on the fore limbs, four fingers on the hind limbs (no pinky). The nostrils located at the front end of the muzzle and the eyes are raised and located on the upper side of the head, which allows crocodiles to stay in the water at its surface, exposing only the eyes and nostrils to the air. The external auditory orifices are closed with movable valves that protect the eardrums from mechanical damage when immersed in water. The body, tail and limbs of crocodiles are covered with large regular shaped horny plates, located on the back and stomach in the correct rows. In the inner layer of the skin (corium), under the horny shields of the outer layer, bone plates (osteoderms) firmly connected with the horny shields develop on the back and in some species on the belly, forming a shell that protects the body of the crocodile; on the head, osteoderms fuse with the bones of the skull.

Modern crocodiles inhabit a variety of freshwater. Relatively few species tolerate brackish water and are found in river estuaries (African narrow-crocodile, Nile crocodile, American American crocodile). Only crescent crocodile  swims far into the open sea and was noted at a distance of 600 km from the nearest shore. Crocodiles spend most of the day in the water. On the coastal shallows go out in the morning and in the late afternoon - warm up in the sun.

Crocodiles hunt at night. An essential component in the diet of all crocodiles is fish, but crocodiles devour any prey they can cope with. Therefore, the set of feeds varies with age: young invertebrates serve as food for young people — insects, crustaceans, mollusks, worms; larger animals hunt for fish, amphibians, reptiles and aquatic birds. Adult crocodiles are able to cope with large mammals. Known case of being in the stomach nile crocodile rhinoceros remains. Many species of crocodiles have cannibalism - devouring smaller ones with smaller ones. Often, crocodiles eat carrion; some species hide the remaining remains of the prey under the overhanging coast and later devour them semi-decomposed. Crocodiles move in the water with the help of a tail. On land, crocodiles are slow and clumsy, but sometimes undertake significant transitions, moving a few kilometers away from water bodies. When moving fast crocodiles put their legs under the body (usually they are widely spaced), which rises high above the ground. Young Nile crocodiles can run gallop at a speed of about 12 km per hour. Crocodiles lay eggs the size of chicken or goose, covered with a lime shell. The number of eggs in a clutch in different species varies from 10 to 100. Some species bury eggs in the sand, others lay in nests made by the female from rotting vegetation. The female remains close to the clutch, protecting it from enemies. Young crocodiles are still inside the eggs, by the time of hatching make croaking sounds, after which the mother digs out the clutch, helping the offspring to get out.

Crocodiles grow rapidly in the first 2–3 years of life, during which they reach crocodiles and gavials. size 1-1.5 m. With age, the growth rate falls, and they add only a few centimeters in length per year. Sexual maturity reaches the age of 8-10 years. Crocodiles live up to 80 - 100 years. Enemies in adult crocodiles are few, if we exclude a person. Reported cases of attacks by elephants and lions on crocodiles, making transitions by land from one reservoir to another.

Africa is widely distributed Nile Crocodile (Crocodylus niloticus). It can be found throughout Africa, except for its northern part, in Madagascar, the Comoros and the Seychelles. Most often settled outside the forest, but comes into the forest reservoirs. It reaches a length of 4-6 m. The newly hatched young cubs are about 28 cm long, reach 60 cm by the end of the first year of life, 90 cm by two years, 1.7 m at 5 years, 2 at 10 years, 3 m and at 20 years old - 3.75 m. The night is spent in the water, and at sunrise the sun comes out on the shallows and bask in the sun. Midday, the hottest hours spend in the water, with the exception of cloudy days. In windy, rainy weather, spend the night on the shore. The maximum duration of stay under water for animals with a length of about 1 m is about 40 minutes; larger crocodiles can be under water for much longer. Food Nile crocodile is very diverse and varies with age. In calves up to 30 cm long, 70% of the food is insects. Larger individuals (about 2.5 m long) feed on fish, mollusks, crustaceans, and even larger ones feed on fish, reptiles, birds and mammals. Adult Nile crocodiles can attack large mammals such as buffaloes and even rhinos. Crocodiles trap animals at watering places, in water or on land in thick grass. In some places, Nile crocodiles are dangerous to humans. Eggs are always laid in the dry season, with low water levels. Females dig a hole in the sand up to 60 cm in depth, where 25-95 eggs (on average 55-60) are laid. Incubation lasts about 90 days, during which the mother remains constant at the nest, guarding the clutch. Apparently, at this time the animal does not feed. By the time of hatching, young crocodiles inside the eggs begin to make grunting sounds, which serve as a signal to the mother, helping the youngs out of the sand and accompanying them to the water. At this time, the female can attack a man even on land. Hatching of eggs usually occurs after the first rains fall, with a rise in the water level in lakes and rivers, so that young crocodiles immediately find shelter and food in the spill-over reservoirs. After the young crocodiles leave the eggs, the mother leads them (according to the observations of Cotta) to the “nursery” chosen by her - a shallow reservoir protected by vegetation. Here, young crocodiles stay about six weeks; All this time, the mother remains with a brood, protecting him from the attacks of predators. In the absence of a mother, crocodile eggs that have emerged from the eggs often remain close to the nest, where they are usually exterminated by predators - goliath heron, marabou, kites. There are numerous cases of cannibalism (devouring eggs and young individuals), which are usually considered to be a mechanism for regulating the number of a species: it is noted that cannibalism is the more often the higher the number of crocodiles. The number of Nile crocodiles everywhere has fallen and continues to fall. AT ancient egypt  crocodiles were revered as sacred animals; now they are nearly wiped out. The same fate will befall crocodiles in several places in Central and East Africa, unless measures are taken to protect the species.

It is difficult, perhaps, to call a more disgusting and terrible animal. Many experts and hunters believe that crocodiles kill more people than lions, tigers, panthers and snakes put together. It is believed that in Africa every year about a thousand people, mostly children and women, become victims of these animals. Crocodiles can be found in Central and South Africa, in hot regions of Asia, on the Pacific Islands lying in the tropical belt, and in northern Australia. They are found in the tropics South americabut there is more common alligator. (It is not difficult for any naturalist to cite many signs distinguishing a crocodile from an alligator. We refer to the most characteristic difference. In an alligator, if the mouth is closed, the teeth are not visible. In a crocodile, two long canines are visible. They seem to rest in the grooves of the upper jaw and create the appearance of a smile).

If you do not take into account several species of tiny lizards from the family of chameleons, then of all reptiles, only the crocodile has a “voice”. His strange, thick roar is reminiscent of not the distant rumble of thunder, or the fraction of a big drum. Crocodile teeth have an amazing ability to recover. Only a tooth falls out - a new one grows on the spot. And so all my life. Crocodile is picky. His gastric juice is so rich in hydrochloric acid that iron arrowheads and even steel hooks dissolve in it for several months. But despite this, observations show that the appetite of the crocodile is small. In captivity, he lacks only 400 grams of meat per day.

A crocodile has two formidable weapons: scary jaws and a mighty tail. With one blow of the tail, he can kill an adult antelope or kill her leg. Most often, the crocodile is kept near the shore. Muddy waters  hide the predator. He silently dives. And then rushes to the victim, seizing it, as in a trap, with its toothy maw.

Very high eyes and nostrils, barely visible on the surface of a lake or river. The body of the crocodile is under water. Like a submarine, the crocodile is equipped with an amazing system of valves that, when immersed, automatically overlap the nostrils, ears and throat. The eyes of a crocodile are unusually susceptible to light, which allows it to see well under water even at night.

The crocodile is one of the few predators that boldly and systematically attack humans. In places where it is sacred (it is fed there), where the waters are teeming with fish, the crocodile is almost not dangerous. But in others, where there is little fish and game, he does not mind eating human flesh. Most often, the victims of crocodiles are women, when they wash clothes on the banks of the river or come for water, and bathing children.

When a crocodile manages to grab some large animal, such as an antelope or a cow, it clears the animal's head with a skillful movement of the head, and then pulls it into the water in a deep place and drowns it. It would seem that you can proceed to the feast, but there are some difficulties. The fact is that the predator's teeth are not adapted for chewing. They serve him only as an instrument of capture. Therefore, the crocodile cracks down immediately with only small animals.

The crocodile pulls large animals away from the shore and waits until the carcass is spoiled and softer. Only then does he tear it apart. Often a crocodile drags his victim into a cave dug under the shore. In it from the water usually leads a kind of tunnel. And through a small hole that goes to the surface of the earth, air enters the cave.

This is an unusual incident with one African. A crocodile grabbed his leg and pulled it to the bottom in front of those present. Fortunately for the victim, the crocodile shelter was only a few meters away. The unfortunate came to himself in a cave. He was surrounded by skeletons and decaying carcasses. The crocodile lay beside. But soon the water began to boil, and he disappeared. Then the African, taking advantage of the absence of the predator, dug a hole through his hands, through which air flowed, and ran away. At home, for a long time they refused to believe the "alien from the world of shadows." (By the way, it would be possible to make good films about Africa with crocodiles in the lead role).

There are many varieties of crocodiles. The most common Nile crocodile living in Africa and Madagascar. The female of this crocodile bears on average 55 eggs. The length of each reaches 8 centimeters. She buries eggs near the water in the sun-warmed sand and patiently waits for the appearance of offspring. Waiting lasts about three months. All this time, the female protects the eggs from the robbers: mongooses, pythons, hyenas, monkeys and monitor lizards (sometimes people also eat crocodile eggs, but eggs smell like fish).

When crocodiles emerge from the eggs, buried under a layer of sand of 50 centimeters, they cannot break the shell in any way. Then they start calling their mother, who seemed to be just waiting for the “SOS” signal. The female immediately begins to rake the sand. This instinct is extraordinary power. One day, scientists conducted an experiment. They protected the egg laying site with a wooden fence. At the first distress call, the female smashed the fence into pieces.

A newborn is small - some 25 centimeters. But from the moment he was born, he shows a rare aggressiveness, sinking his teeth into everything that comes his way. Having hatched from an egg, the newborn immediately rushes to the water, seeking salvation there from many birds and animals - storks, cranes, adult crocodiles, which find the meat of young predators more tasty than eggs. Having counted all his enemies, some experts say that out of a hundred newborns, only one manages to live to a mature age.

Crocodiles live a hundred years or more. They belong to those rare animals that grow up to death, but with age their growth slows down. It is said that crocodiles of the islands of the Pacific Ocean and Asia happen to reach 9 meters. As for the Nile crocodiles, for the last time not a single hunter can boast that he killed a crocodile longer than five and a half meters.

And the number of hunters is growing. Prices for shoes, bags and suitcases from crocodile leather are rising, and demand is not decreasing. Toothy critters that came out victorious in the fight against centuries, according to experts, lived on the planet one hundred million years ago, and now civilized hunters are dying from the bullets. Naturally, predatory lizards disappear. Scientists predict the imminent disappearance of the Nile crocodile. But few people share their concern. Hunters claim that crocodiles simply move to inaccessible areas, escaping from the noise of civilization and a restless neighborhood with a person.

A different view of African countries. Many of them have limited hunting for crocodiles (created reserves). So, on Lake Victoria in Uganda there are a huge number of crocodiles, the largest in Africa, and perhaps in the world. The waters of the lake are teeming with fish, and a hungry crocodile can only open its mouth to get enough of it. Crocodiles lie on the shore. Sometimes it is so tight that some sit on the backs of their fellows. They resemble fallen trunks of ancient trees burned by time.