Crocodiles are a detachment of the class of reptiles, distributed mainly in the southern hemisphere of the Earth. Its representatives have established themselves as ferocious and dangerous animals that leave no chance for those who meet on their way. At the same time, among crocodiles there are modest and shy individuals who can only handle small prey. Let's learn more about these animals.
Crocodile squad: general characteristics
Crocodiles are large reptiles that existed as far back as 83 million years ago. Although they are reptiles, they are genetically much closer to dinosaurs and birds than they are to turtles or snakes.
Today, the order of crocodiles includes 23 species that belong to the family of alligators, gharials and true crocodiles. As a rule, these are powerful lizards with short and strong limbs, sharp teeth and strong jaws. Characteristic features of the crocodile squad are an elongated and slightly flat body, a long tapering tail and a large head. The snout of animals also tapers at the end.
Their ears, eyes and nostrils are located at the top of the head, which allows animalscompletely submerged under water, leaving only these parts of the body above its surface. The largest species weigh up to 2 tons. But, despite this, all crocodiles swim perfectly and run fast enough. On land, they can accelerate to 17 kilometers per hour.
Traditionally, crocodiles are considered green. But in reality, the range of their coloration is much wider and largely depends on the specifics of their habitats. The belly of animals is usually light beige tones, but the back can be from light yellow, gray and brown, to dark green and black. Often there are various spots and stripes in the color. Crocodiles are truly green when they just emerge from the water and the skin has not yet had time to dry.
Diversity of species
Representatives of the crocodile order are easy to recognize among other reptiles, but they are often confused with each other. It is possible to distinguish predators, first of all, by the structure of the muzzle. In real crocodiles, it narrows in the shape of an English V, and the upper teeth always look out of the closed mouth. Alligators have a more rounded snout and look like the letter U, and their teeth are almost invisible. Gharials have the most striking difference, because their mouth is very narrow and long. A huge number of teeth peek out from it, which are directed to the sides to make it harder for prey to free themselves.
The largest in the detachment are combed crocodiles. Their males reach 5-7 meters in length (including the tail) and weigh about 2,000 kilograms. They prefer large prey, and sometimes even attack their own kind. Second afterThey are the Nile crocodiles that live in Africa. On average, they reach 4-5 meters in length. Nile and combed species are characterized by increased aggressiveness, they most often attack people.
The smallest and shyest in the detachment are blunt-nosed crocodiles. Their body reaches only 1.5-2 meters in length. They are regularly attacked by more dexterous and larger predators, so they are secretive and extremely cautious.
Habitats
Representatives of the order of crocodiles live in the tropical regions of the planet. Their distant ancestors lived on land, but modern species lead a semi-aquatic lifestyle. They prefer fresh lakes, rivers or tropical swamps, where they spend most of their lives. At the same time, reptiles feel great even in water bodies with high salinity and are found even off the coast of the seas. S alts from the body help them to remove special glands located in the eyes and mouth. The legend of "crocodile tears" that they pour when killing prey is widely known among the people. Reptiles really "cry", but not out of pity, but from an excess of s alt.
The range of crocodiles covers almost all of Africa, most of South America, the northeast coast of Australia and all of Oceania. They live throughout Central America and on the coast of Mexico, in the states of Florida and Louisiana (USA). In Eurasia, they are found from Pakistan to the Japanese islands.
What do they eat?
Crocodiles are predators. Small and medium species consume fish,mollusks, crustaceans, various lizards, snakes and mice. S alted crocodiles living on the Pacific coast of Australia eat even the poisonous toad-aga. The diet of the Ghanaian gharial includes only fish, with which the unusual shape of its jaws is associated. In fact, the theory is not very confirmed, because its close relative, the gharial crocodile, also eats monkeys, otters, deer, pythons, wild pigs and other animals.
Large species of crocodiles are quite capable of coping with strong and adult prey. They prey on buffaloes, livestock, zebras, antelopes, dolphins, sea turtles, sharks, birds flying over the water. They do not chew their food, but swallow it. Larger prey is first torn to pieces by crocodiles moving their necks from side to side.
Features of physiology
The body of crocodiles is covered with a dense stratum corneum. It consists of dead cells, so molting is not characteristic of animals. From above, their skin is covered with round bone plates, under which there are various channels and cavities with nerve cells and vessels.
On land, reptiles seem slow and clumsy, but in the water they can accelerate up to 30 km/h. More than 50% of their body is made up of muscles, which provide significant power. The bite of a crocodile is considered the strongest among all existing animals. In the largest species, it ranges from 145 to 340 atmospheres.
Crocodiles see perfectly. Their narrow vertical pupils give a 270-degree field of view, leaving blind spots in front of the muzzle and aboveback of the head. Unlike other reptiles, they have good hearing. The shields on the skin perform a tactile function and are tuned to be sensitive to vibration. This helps the animals navigate the water.
Lifestyle
Most of the time crocodiles spend in water. They land on land early in the morning or in the evening. They are cold-blooded, so their body temperature depends on the environment. For thermoregulation on hot days, they open their mouths so that moisture evaporates faster.
Some reptiles live alone all year round, others calmly endure the company of relatives. Their communication with each other resembles a growl, and during the mating season it turns into a real roar. When it comes time to breed, they become possessive, fiercely defending their territory. Crocodiles lay their eggs on the coast, burying them in sand, silt or covering them with foliage. The gender of the babies depends on the temperature of the nest. Males hatch only at 31-32 degrees, with a deviation from this norm, only females appear.
