MOVEMENT IN A SNAKE :

or ;

ifyouwannaknowwhytheycrawlreadon:-)

a true moving story by Gijs  van Waversveld

last upload : 06-10-2002

No frames ? click here to go 

One surprising characteristic of snakes is their ability to move rapidly without the use of legs. Four quite different types of locomotion are used by snakes in getting from place to place.

The most frequently used method is the simple, undulating crawl, which is called the serpentine method. In this type of locomotion, the snake pushes against the ground on the back side of each curve or undulation and flows smoothly forward.

In another method called caterpillar, or rectilinear, used only by the heavier-bodied snakes, the skin of the ventral surface is moved forward and backward by strong muscles, and the broad belly scales grip the ground, moving the snake forward in a straight line. This method has given rise to the erroneous statement that snakes "walk on their ribs"; actually the ribs do not move forward and backward in any of the four types of movement.

Several desert-dwelling species use a special type of locomotion, called sidewinding, to move on loose or hot sand. In this method the snake rolls its body along sidewise along the ground in a looping motion.

The fourth method is known as concertina, because the body is alternately stretched out and pulled together as the snake moves from one anchor point to another. The concertina is used in crossing smooth surfaces and in climbing. The most common of the four, and the one that enables all snakes to achieve maximum speed, is the serpentine method. Not all snakes can use each of the other methods.

 The fastest recorded speed achieved by any snake is 13 km/hr (about 8 mph), slower than a human adult can run, but few can go that fast. In climbing, any of the methods except sidewinding may be used, but snakes swim only by means of the serpentine method. The so-called flying snakes of Southeast Asia and New Guinea do not actually fly, but they can drop or hurl themselves from fairly high trees and fall or even partly glide to the ground without injury.

Structure and Function

The long, slender body of the snake contains a large number of vertebrae, never fewer than 100 and sometimes more than 300, each with a pair of ribs except the first two.

The skeleton is light in structure and is modified to provide great freedom of movement. The skull in particular is loosely built and can be stretched in several directions, permitting the snake to swallow large meals in relation to the size of the head and body. This mobility can be seen especially in the two bones of the lower jaw, which are attached to the skull by a short, movable bone and which are united at the front end merely by an elastic ligament. Both jaws hare a large number of sharp, needlelike teeth, all curved toward the rear of the mouth.

The teeth are arranged in six rows paralleling the long axis of the head - that is, two rows on each side of the upper jaw and one on each side of the lower jaw. Except in venomous species, the teeth are solid and are replaced periodically. When the snake catches its prey, the recurved teeth enable it to retain a firm hold.

The prey is killed quickly by suffocation and swallowed by alternate movement of the rows of teeth, which work to pull the prey into the mouth. As the food passes through the mouth, it is covered with saliva; contrary to popular opinion, snakes do not cover their food with saliva before taking it into the mouth. Most meals are swallowed easily and quickly, but a truly large meal may require several hours. The big pythons can consume animals that weigh up to about 68 kg (about 150 lb), but swallowing such a meal is a laborious process.

Wanna read more on how the capturing and feeding process goes, use the following links... :

STAGE 1  : PREY DETECTION

STAGE 2 : PREY CATCHING

STAGE 3   : STRANGULATION  PARENTAL ADVISORY

STAGE 4 : PREY EATING   PARENTAL ADVISORY

 

THIS PAGE WAS GIVEN TO ME BY SOMEONE WHOSE MAIL ADRESS I LOST !!! MAIL US IF THIS IS YOURS...