Snakes are reptiles with an elongated body that is flexible and limbless. Like all reptiles, snakes are cold-blooded, which means they do not have the ability of generating adequate amounts of heat in order to keep their body temperature at a constant level. Instead, they are dependent on the heat from their surroundings and the sun to control the temperature of their body.
Many species of snakes have skulls with more joints than their lizard ancestors. This enables them to swallow prey much larger than their heads. Their jaws are highly mobile. To accommodate their narrow bodies, snakes’ paired organs (such as kidneys) appear one in front of the other instead of side by side, and most snakes have only one functional lung.
15 families of snakes are recognized with close to 3000 species.
The skin of a snake is covered in scales. Contrary to the popular notion of snakes being slimy because of possible confusion of snakes with worms, snakeskin has a smooth, dry texture.
Another interesting fact about snakes is that they need to shed their skin regularly while they grow, a process known as molting . Moulting serves a number of functions. Firstly, the old and worn skin is replaced; secondly, it helps get rid of parasites such as mites and ticks.
Most snakes use specialized belly scales to travel, gripping surfaces. The body scales may be smooth, keeled or granular. Snakes’ eyes are covered by their clear scales (the brille) rather than movable eyelids.
Their eyes are always open, and for sleeping, the retina can be closed or the face buried among the folds of the body.
Snakes use smell to track their prey. They smell by using their forked tongues to collect airborne particles, then passing them to the Jacobson’s organ in the mouth for examination. The fork in the tongue gives snakes a sort of directional sense of smell and taste simultaneously. They keep their tongues analyzing the chemicals found, and determining the presence of prey or predators in the local environment.
Snakes can be oviparous or ovoviviparous. Colubrids are generally oviparous with few exceptions. Most elapids (which include cobras, coral snakes and all other fixed-fang snakes) produce eggs, which are not maternally incubated or protected.
Pythons are, by nature, egg layers. Boas give birth to offspring that must only extricate themselves from the thin mucous membranous sack upon arrival into the world. Typically all vipers, even pit vipers, are ovoviviparous
Cobras, vipers, and closely related species use venom to immobilize or kill their prey. The venom is modified saliva delivered through fangs.