In the modern world, it is generally accepted that crocodiles are distant relatives of dinosaurs. Indeed, in their appearance, one can imagine what giants the ancient monsters were. Today, crocodiles are well studied and assigned to a separate class. However, people often confuse which one. Crocodile - reptile or amphibian? What is the difference between these two classes? Let's take a closer look at them.
Class Amphibians
Amphibians, or this class is also called amphibians, is very different from all other vertebrates. The very first difference is that they have two stages of development. The first - at a young age, amphibians look like fish. They also have a tail, gills and they are all born in water. The second stage in development is the release of amphibians from the water and the restructuring of the whole organism for life both in water and on land: the lungs develop, the tail disappears. The most obvious example in this case is a frog.
Given such differences, why the question arises: is a crocodile a reptile or an amphibian? The fact is that a crocodile lives in water, has lungs and, to some extent, can also be considered an amphibian. But he does not have stages of rebirth, like amphibians. Crocodiles are born already fully formed and not in water, but on land. And only after a while they return to the aquatic environment. Now consider why a crocodile is a reptile.
Class Reptiles
The Reptiles class includes not only crocodiles, but also snakes, turtles and lizards. Everyone has similarities to amphibians and there are many differences. So, all reptiles are cold-blooded animals. Therefore, their main habitat is the tropics and subtropics. In addition, the body of reptiles is covered with scales that protect delicate skin. The crocodile has such strong skin that it is impossible to just damage it. Interestingly, unlike other reptile species, crocodiles do not fade, and their skin grows with them.
Another difference from amphibians is the structure of the skeleton. All reptiles have cervical vertebrae that allow you to turn your head. In addition, reptiles do not have skin respiration, as in amphibians, but breathe due to the developed respiratory system. Even in all reptiles, fertilization occurs inside the body, unlike amphibians, and cubs are born fully formed.
Features of the structure of the crocodile
Crocodile in its structure differs not only from amphibians, but also from most reptiles. The crocodile's appearance is awesome, and it really looks like dinosaurs that lived in antiquity. The length of the reptile is from 2 to 6 meters, it inspires fear. The head is arranged in a special way: it is flat, with a long snout on which the nostrils are located. The eyes are located at the top, and when in the water, the crocodile can expose only the eyes and nostrils. In this case, it is very difficult to notice.
In addition, the heart of a crocodile differs from a similar organ in other reptiles in that it has four cameras, not three. This indicates a more perfect circulatory system and brings the crocodile closer to mammals. But in the circulatory system of the crocodile there is a controlled system for mixing arterial blood with venous. This helps in the digestion process and prevents infection from being in dirty water.
Breeding
Another sign by which you can determine whether a crocodile is a reptile or amphibian is the method of reproduction. A female crocodile lays eggs, but not in water, like amphibians, but on land. She bury them in the sand near the water. The female herself guards the nest from uninvited guests, being not far from the masonry. Interestingly, all eggs hatch at the same time, and the sex of the babies depends on the ambient temperature. If the temperature exceeds 34 degrees, the females will hatch, and if it is in the range from 30 to 34, then the males will hatch.
Just before the birth of the little crocodiles give the mother a signal, and she carefully digs out the masonry, helping them get out of the nest. This is not done by all the other reptiles. At the same time, the crocodile also transfers its babies in its mouth to the water. One can imagine how these huge jaws gently take crocodiles and move them into a pond. Also, sometimes crocodile helps to get to the water and newborn turtles.
Types of Crocodiles
In nature, there are 21 species of crocodiles. All of them differ in size, habitat and structure of the head. Most often confused crocodile and alligator. An interesting point: they differ in the structure of the muzzle. In a crocodile, it is sharp, and in an alligator, it is more dull. Teeth with a closed mouth are visible only to crocodiles. The heart of a crocodile pumps blood faster, and due to this, salt metabolism is faster than that of alligators. This feature allows crocodiles to live not only in fresh water, but also in the sea.
There are small crocodiles, for example caimans, which can be kept at home. This often happens because the cayman is able to adapt well to any conditions. The only thing that he lives only in clean water, and it is easy to create in a house or zoo.
Perhaps this article helped you sort out the question: is a crocodile a reptile or an amphibian?