Snakes are long, limbless reptiles, living mostly in the warm regions of Earth. They are predators. They kill their prey with poison (known as venom) or by constricting (squeezing) it to death. There are about 2500 species of snakes. Snakes have no ears and sense their prey from vibrations on the ground. They use their flickering tongue to smell. Their eyesight is poor and they can see things only when they are close. About one-third of all snakes are venomous, but few have poison strong enough to harm humans.
Classification of Snakes
Snakes originated from terrestrial lizards in the Middle Jurassic era (174.1 to 163.5 million years back). The oldest discovered snake fossil dates back to 167 million years. The scientific name of a snake is determined based on the characteristics and other factors. Snakes fall under the suborder Serpentes which is why they are commonly called serpents. As mentioned earlier, they are reptiles but with no wings and limbs. All they have is a slender elongated cylindrical body and a tail. This species falls under the same order Squamata of lizards. Hence, the classification of a lizard represents a snake. Due to the evolutionary process, the snakes have lost their limbs and developed various physiological features.
They have undergone simplification and structural reduction. They have also increased a special feature and lost some. Remember that not all limbless reptiles are snakes. There are burrowing lizards that also have lost their limbs due to evolution. The only difference between such lizards and snakes is that the former have eyelids. Snakes do not have eyelids and tend to give a deadly stare. One of the interesting snake characteristics is that it has lost its urinary bladder. Due to its slender body and cylindrical shape, all the organs are elongated and sleek. In fact, the left organs are greatly reduced in comparison to the right organs.
Characteristics of Snakes
As mentioned earlier, snakes are reptiles with no limbs. Some of the species have vestigial traces of hind limbs that show the perfect evidence of evolution. It tells us that they evolved from limbed lizards back in the Jurassic era.
The snake characteristics also tell us that they have horny scales all over the body. The scales and skin are well clasped. They shed their skin a few times a year. A shed skin shows the configuration of the scales perfectly. On the other hand, the number of vertebral discs has increased. It also has developed an organ that secretes venom. It also has developed the tracheal lung as a breathing system.
Another remarkable feature of snakes is that the organs are not oriented bilaterally rather they are placed side by side. The jaws of the snakes are not fixed but are loose so that they can gobble prey larger than their head. The bones in the head also support gobbling prey. The teeth are backwards curved and are fused with the head bones. They do not have any ears, as well as movable eyelids. It means that snakes are unable to receive any sound waves. It can perceive sound waves of frequency ranging from 100 Hz to 700 Hz with its skull bones.
It has a remarkable chemosensory organ developed on the roof of its mouth that receives chemical stimuli from the bifurcated tongue. You will observe that the tongue comes out, lashes a few times, and then enter the mouth to provide the chemosensory information gathered. These are the snake characteristics that distinguish it from the other reptiles. Snakes do not have any vocal cord or larynx to produce sounds but they can hiss.
The Life Cycle of a Snake
As the snake lower classifications suggest, it is a reptile and will lay eggs. Hence, life begins from an egg.
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