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Animal Kingdom - Reptiles
ReptilesClick thumbnail to view full-size
Snakes, lizards, crocodiles, tortoises and turtles are all reptiles. They belong to the reptilian group of animals. All the animals of this group crawl and, therefore, are also called crawling animals. Today, there are around 5,000 species of the reptiles. They came into existence some 500 million years ago. The reptiles are divided into three categories- the Chelonian, the Squamata and the Crocodilian.
Reptiles are cold-blooded animals, that is, their body temperature rises or falls according to the temperature of their environment. Their skin is dry, rough and covered by horn scales. The skeleton is made of bones. Respiration in them takes place through lungs. Females lay eggs on land.
The reptiles of the chelonian group have their body enclosed in a hard shell of bones. Their jaws are without any teeth. Various kinds of tortoises and turtles are included in this group, which are generally found in water and damp places. These creatures have teeth on both their jaws. Their hearts are divided into four parts. They have sexual breeding.
The reptiles of the squamata group include various kinds of lizards. This group is divided into two sub categories- the lacertilian and the ophidian.
Various kinds of lizards constitute the lacertilian sub category. These lizards have five toes on their legs. There are claws at the ends of the toes. The toes have lamellae which facilitate the easy movement of lizards both on the smooth, surface and on the walls. In the cavities below their eyes lie the tympanic membrane. They have mobile eyelids. These animals can shake off their tails. They ca again have new tails after shaking them off.
All varieties of snakes come under the ophidian sub-category. Snakes have a long, cylindrical body covered with dry scales. They do not have legs, backbones, bladder and tympanic membrane. They have only one lung for breathing. Their tongue is long and divided into two parts at the front end. It is through their tongue that snakes feel and smell. They have excellent eyesight. They do not have ears. Sounds are conveyed to these animals through the vibrations of the earth. Erex Jony is a two headed snake. Python is the biggest snake.
Gavilis, crocodiles and alligators are included into the crocodilian sub category. They are carnivorous animals. Their thick skin is covered by hard scales.
Their fingers are connected by a membrane. The nostrils are situated at the tip of their mouth. Though these animals live in water, their females lay eggs in pits on land. These animals are founded in rivers and lakes. These are the largest of the existing reptiles. The estuarine species of the crocodile measures as long as 7.5 meters 25 feet. The largest crocodile, ‘crocodiles’ is the heaviest of all the crocodiles. It weight 525 kg.