They might lack arms and legs, but snakes are surprisingly mobile.
Given that they have nothing by way of legs, arms or wings – or indeed any sort of appendage – snakes have a surprising array of tricks under their scales when it comes to getting from A to B.
Here we explain how they move…
How do snakes move?
A snake’s body is long and strong, comprising a flexible spine and hundreds of sharply curved rib bones (up to 400 in some species). Engaging the muscles attached to these rib bones allows snakes not only to slither, but to climb, swim and even fling themselves through the air.
On land, snakes utilise four basic modes of travel, depending on their size, the habitat and what’s going on around them. Many are capable of more than one mode, switching between them as the need arises.
How do snakes slither?
Lateral undulation (or serpentine) is the most common. This undulating, side-to-side pattern of movement is probably what comes to mind when we visualise a slithering snake. An individual uses its S-shaped loops to push off from irregularities in the ground or features in the landscape, such as rocks and logs, resulting in a forward propulsion. If the ground is featureless or unstable (a sand dune, for instance), this mode of locomotion is more difficult.
Snake’s concertina movement
Concertina movement is how it sounds. A snake stretches out and anchors the front section of its body, then pulls up the rear, bunching itself into an ‘S’ pattern. Then, it anchors the rear part of the body, stretches forward, and starts the process again.
How do snakes move sideways?
Sidewinding (or lateral displacement) is a neat adaptation to hot or unstable ground. As the name suggests, this is a sideways movement in which a snake lifts parts of its body off the ground while also pushing to the right or left. A sidewinding snake will often leave a characteristic series of squiggles in its wake.
Can snakes move in a straight line?
Linear progression (or rectilinear) is a straight-forwards mode of travel often used by larger snakes and those that live underground, in which the body remains in a long line. An individual uses loose belly skin and muscles to reach forward, then the body catches up. This happens simultaneously and quickly at many points along the body and appears as a continuous, smooth motion.
So, as the snake said to the millepede, legs aren’t everything.
Main image: horned adder moving across sand, Africa © Martin Harvey/Getty