Crocodiles are not amphibians. They are reptiles. Crocodiles are reptiles that belong to the group known as crocodilians. The group of crocodilians also consists of reptiles such as the alligator, caiman, and gharial. Crocodilians are large animals with long, lizard like bodies with short pairs of legs. They have a lizard type shape and long snouts. Their hides are tough and scaly and their teeth are very sharp.
These crocodilians are water dwelling animals that prefer to live in large bodies of shallow water, sluggish rivers, and/or open swamps. They are equipped with webbed feet so that they can walk easily on the soft, wet ground. Their strong, long tails enable them to swim and move easily about in the water.
For food, crocodilians eat small animals such as birds, fish, and rodents which they swallow whole. Occasionally large crocodiles may attack large animals and/or humans. The saltwater and nile crocodiles of Africa are the largest species as well as the most vicious. They are killers that have been known to sometimes even leave the water to attack a human being. It is said that crocodiles keep on growing until they die, which in turn makes them difficult to keep as pets.
There are four reptile orders in existence today. Crocodilia refer to animals such as crocodiles and alligators. Squamata refers to lizards, snakes and other similar creatures. Turtles are categorized into the Testudines order and the order of Rhynchocephalia contains only two species known as tuataras, which are native to New Zealand.
Reptiles and amphibians are distantly related to one another and have quite a few similarities. However there are still many differences that can be found between the two. These differences can often be distinguished from each other based off of physical appearance and the different stages of life.
The word amphibian literally means “living double lives”. This refers to creatures who are living two lives: one in water with gills and the other on land once they grow lungs with age. Amphibians are vertebrates and cold blooded. Early amphibians were the first animals to leave sea and eventually venture onto land.
Whereas the word reptile means “to creep stealthily under cover of darkness” this group of animals has scales, breathe air and usually lay eggs. Most reptiles live on land and reproduce by laying eggs.
Amphibians breathe under water through gills until they develop lungs later on in life, whereas reptiles such as the crocodile are born resembling miniature adult crocs with already working lungs ready to breathe air from day one. An amphibian’s skin texture is smooth, moist and rather sticky. It is laden with mucuous glands and although most amphibians have lungs most breathe through their skin and the lining of their mouths. Reptile’s skin is dry and scaly. Amphibians usually have to stay near water sources to prevent drying out whereas reptiles do not. Crocodiles actually have a muscular diaphragm that pulls part of the pelvis back and brings the liver down, thus freeing space for the lungs to expand. This type of diaphragmatic setup is known as the hepatic piston.
Amphibian’s eggs are soft and covered by a gel. They do not have a hard protective covering and are usually found in water or damp places. Reptiles lay amniotic eggs with hard leathery surfaces. They usually lay these eggs on land or keep them inside of their bodies until they are ready to hatch.
Both amphibians and reptiles are equipped with ways to defend themselves against predators. Amphibian’s have toxic skin secretions and are known to bite. They do not however have claws or nails. Reptiles such as the crocodile do have claws, as well as whipping tails that can really do some damage. They are also obviously known to bite, and some even have venom.
Reptiles originated around three hundred and some odd million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Unlike amphibians, reptiles do not have or require an aquatic larval stage. Interestingly enough, it did not become known until around the nineteenth century that reptiles and amphibians are two different types of animals.