How Do Snakes Move Without Legs? 4 Ways Snakes Get Around

The body behind the movement

A snake’s skeleton is mostly backbone. Depending on the species, it has roughly 200 to more than 400 vertebrae, compared with 33 in a human, and almost every vertebra in front of the tail carries a pair of ribs. The joints between vertebrae allow a lot of side-to-side bending and some up-and-down movement, but very little twisting, which keeps the body stable. See Do snakes have bones? for more on the skeleton.

Layers of muscles connect the vertebrae, ribs and skin. By contracting muscles on one side and then the other, a snake sends waves of bending down its body.

The belly scales matter too. Most snakes have a single row of wide ventral scales whose back edges overlap like roof tiles. A 2009 study led by David Hu found that these scales create more friction when a snake slides sideways or backward than when it slides forward, so a snake can push off without slipping back. The study also found that snakes lift parts of their bodies slightly as they move, shifting their weight onto the points that give the best grip.

1. Lateral undulation: the classic slither

Lateral undulation is the S-shaped movement most people picture. The snake bends its body into curves that travel from the head toward the tail. The outer side of each curve presses against rocks, plants, roots and bumps in the soil, and those push points shove the snake forward.

Because each part of the body follows the path of the part in front of it, a snake can weave smoothly through grass and around stones. It is the most common way snakes move on land and the main way nearly all snakes swim, as described in Can snakes swim?. The common garter snake, for example, uses it to dash through grass and to swim across ponds.

2. Concertina movement: bunching and stretching

When there is no room to slither, such as in a narrow burrow or along a branch, snakes switch to concertina movement, named after the folding musical instrument:

1. The snake bunches the back part of its body into tight curves and braces it against the walls or the surface.
2. It stretches the front part forward.
3. It anchors the front part and pulls the back part up behind it.

Concertina movement is slow and tiring, costing several times more energy than slithering the same distance. It is also how many snakes climb, as explained in Can snakes climb trees?. The corn snake uses it to move through rodent tunnels and up tree trunks.

3. Rectilinear movement: crawling in a straight line

In rectilinear movement the snake keeps its body almost straight. Muscles lift sections of the belly skin, pull them forward and set them down, and then pull the body along over them, so waves of movement ripple along the belly like a caterpillar’s. The ribs stay still.

This is the slowest way snakes move, but it is quiet, smooth and hard to notice. Heavy snakes such as large pythons, boas and vipers use it to creep up on prey or slip along walls and logs.

4. Sidewinding: moving across sand

Sidewinding is used mainly on loose sand and slick mud, where there is nothing to push against. The snake lifts most of its body off the ground and throws it sideways in loops, keeping only two or three short sections in contact with the surface. Those sections stay still while touching down, so they do not slide, and the snake moves at an angle to the direction its head points.

The result is a set of separate, J-shaped tracks across the sand. The sidewinder rattlesnake of the deserts of the southwestern United States and northwestern Mexico is the best-known example, along with some desert vipers in Africa and the Middle East. A 2014 study by Hamid Marvi and colleagues showed that sidewinders can climb sandy slopes by increasing the length of body in contact with the sand. Contrary to a common belief, sidewinding is not mainly a way to avoid hot sand.

Other ways snakes get around

Snakes switch between modes quickly, often within a few seconds, depending on the surface.

How fast do snakes move?

Snakes look fast because their movement is fluid and they disappear quickly into cover, but most are slow compared with people. Studies of lateral undulation have rarely recorded snakes moving faster than about two of their own body lengths per second, and most move much more slowly.

Many common snakes travel at a few kilometers per hour when moving purposefully. The black mamba, widely called the fastest snake, travels at about 11 km/h (7 mph), with possible short bursts of around 16–20 km/h (10–12 mph); see How fast is a black mamba?. An adult person walks at about 5 km/h (3 mph) and jogs at about 8–10 km/h (5–6 mph).