The origin of crocodiles
The history of the origin of crocodiles originates from the times of 200 million years ago. It was the end of the lizard era. But unlike the current crocodiles, who prefer water more, those individuals lived on land.
Crocodiles are representatives of archosaurs, the only ones that have survived to this day. Over millions of years, outwardly almost unchanged. These are highly developed reptiles. Outwardly similar to a lizard. The color is greenish-brown. The weight of an adult crocodile is 500-600 kg. Body length 3-8 meters. An elongated muzzle that allows you to deftly grab prey and hold it tight. Highly developed brain. Great memory. Eyes with narrow pupils protrude above the level of the head.
Crocodile teeth
The teeth are sharp, of different sizes, hollow. New teeth grow in this cavity. In total there are 64-70 teeth. The exact amount depends on the species. Although the mouth of a crocodile with its sharp teeth looks awesome, but he does not chew prey. The teeth are needed, rather, to hold, then the production is simply swallowed. In a crocodile, they change several times in a lifetime.
The nasopharynx is separated from the oral cavity by the palate. In this regard, an individual with an open mouth in water can breathe air through the nostrils that remain above the surface of the water.
The crocodile has a powerful tail. Short legs with membranes. However, it can reach speeds of up to 20 km / h. Leather - rectangular squared horn plates arranged in perfectly straight rows. Above the throat there is a special valve that does not allow water to pass through, and air flows through the nasopharynx behind the valve.
Stones in the stomach of a crocodile
This animal has keen hearing and excellent eyesight. In a thick-walled stomach of an individual, stones are constantly present. Some argue that they are needed to grind coarse food, others argue that the stones in the stomachs give the crocodile balance and stability when it is in the water.
These predators do not have a bladder. The unique circulatory system - four chamber heart, and a special mechanism for mixing blood from veins and arteries regulates blood supply. Light crocodiles can hold a large amount of air.
Crocodiles are taken very seriously to the continuation of the genus. They become overly active, males - aggressive. Rival battles often happen, where crocodiles do serious damage to each other. With the help of certain sounds, males invoke females.
The glands in the throat secrete a musky secret. The female, preparing for procreation, prepares a mound near the water with a height of one to two meters from branches, mud and mud. Then he makes a depression in it. Then it lays from 30 to 80 oval-shaped eggs. The female “insulates” the laid eggs with grass, branches and protects her offspring. There must always be a moist environment in the nest. To do this, the female regularly beats her tail in the water, spraying the nest.
Some time before birth, the female hears the voices of her cubs through the shell. Then the sounds get more and more loud. Thus, small crocodiles ask for freedom. If at the time of birth one of the cubs could not break the shell itself, the female herself crushes it slightly with webbed feet.Only a small percentage of cubs live to adulthood. More often than not, they become small prey for birds of prey, large lizards and other animals.
Interesting fact: The crocodile’s usual lifespan is 90 years.
Crocodiles calmly relate to salt water, but a favorable environment is fresh water bodies. Most of life is in the water. They go to land a couple of times a day - early in the morning with sunrise and in the evening at sunset. The crocodile is cold-blooded. The usual temperature of his body is 33-36 degrees.
What do crocodiles eat?
Crocodiles hunt around the clock. The frequent food on their “menu” is fish. Also, many invertebrates, terrestrial, are eaten. Attack any animalswith the power to cope. There are times when a crocodile can eat another crocodile, a smaller one. Crocodiles can bury food in reserve. More than 50% of food goes into fat. This saves them in long hungry times. By the way, without food, he can live a whole year.
Crocodiles and people
For people, the crocodile is undoubtedly dangerous. There are several types of crocodiles. One species never attacks people, the other - always attacks. In any case, approaching them is strictly prohibited. This is a predator. Crocodile skin is used in the manufacture of wallets, belts, bags.
For poachers, it’s just a business, and very profitable. In this regard, there is a sharp reduction in this individual. The whole view disappears. This leads to a violation of the ecological balance.
