Of all the many different ways to move, the slither of the snake has been one of the most fascinating and envied.
While us humans might not like to crawl on our belly, we're still envious of the fact that snakes seem to glide across the ground with the greatest of ease. A fluid movement that leaves many of us in awe.
How, though, do snakes perform this amazing way of moving? By using some fairly simple strategies along with some specialized muscles and long bodies.
Firstly, we need to think about movement itself. Movement is simply a part of a creature's body propelling itself through it's environment, usually by pushing off the environment itself.
Feet push against the ground, tails push bodies through the water, and wings push bodies through the air. So what about snakes? Well they push too.
Snakes employ the same strategies that all other animals do to move. They push off of their environment, but instead of limbs they use their bellies, tails, and even their heads!
There are four different types of movement, starting with horizontal undulatory progression, or lateral progression for short.
This form of locomotion is the kind most commonly seen. It is used by most small to mid-sized, to fairly big snakes, and is incorporated in areas where the terrain is rather uneven or variable.
This method of movement is accomplished by the snake lashing it's body back and forth, causing lateral waves that force longitudinal motion. To put it another way: they go forward by moving sideways.
Secondly there is, rectilinear progression. This method is employed by the heavyweights of the snake kingdom! But, all snakes are capable of doing it.
Now instead of lashing back and forth across the ground, the snake moves in a straight line in a way not too unlike snapping a jumprope vertically.
Next is concertina progression. This mode of movement can almost be thought of as a snake taking steps.
In concertina progression the snake brings together it's fore and hind halves, causing one or more horizontal loops to form from the mid-body.
Then either the head or tail (head when straight, tail when curled) are anchored into the ground via those ventral spikes, and the body (in the case of the tail anchoring) is shot forward until the whole body is straightened.
Then the snake anchors it's head and brings it's tail together again.
Lastly, the snake can move via sidewinding.
This is by far the epitome of snake locomotion, sidewinding is the equivalant of the horses gallop, and is the fastest mode of movement.
Sidewinding is basically the snake running across the sand!
In sidewinding only two portions of the snake are on the ground at one time.
Much like the concertina progression both the head and tail are used, but now a third portion of the body is employed. The middle.
With the snake firmly anchored with both head and tail, it thrusts it's mid-portion forward, as the mid-body lands, the head is telescoped forward.
When that lands the tail starts coming up. As the tail comes up the mid-portion again is thrust forward, then head, then tail and so forth.
This movement creates vertical pressure on the ground much like that of a foot pushing down, and allows the snake to move forward with out slip sliding away!