Yes, snakes can crawl and slither backwards. There are videos online showing that they can do so, and many snake owners attest to this capability.
However, there seems to be an endless debate about this. Most scientists will say that snakes cannot crawl backward.
A lot of people say that snakes just coil back and then lunge forward. There is even a book in Amazon that claims snakes cannot crawl backwards. But videos show otherwise!
How do Snakes Crawl Backwards?
Snakes crawl backwards with the same muscle groups as they crawl forwards. For example, they curl their bellies, but instead of moving forward, they move back.
While it is rare, snakes also retreat backwards. The most compelling evidence of this comes from a YouTube video where a tiger snake crawled back under a log. In this video, the content creator took a good shot of the snake moving back:
In this video, the snake slithered backwards and showed minor signs of curling its body. However, it was as if it just moved back using the rectilinear motion.
There was even an incident of a snake crawling backwards in a weep vent (shown below). While the rest of the snake’s body cannot be seen, it is evident that snakes can move back and not just curl to strike:
Why Do Snakes Rarely Crawl Backwards?
It does not make sense for snakes to crawl backwards. While snakes do not have good eyesight, all animals evolved to move forward.
In the animal kingdom, all animals walk forward because it is part of the evolutionary process. Animals have to see where they are going. Their movements, in coordination with their sense of vision, is what keeps them safe from predators. It is the same motion that allows them to hunt prey.
Forward motion is also crucial to animals that have poor eyesight. For example, although bats are not completely blind, they move forward in response to their sonar reception.
Animals have few added benefits of walking or swimming backwards. But, moving back can be an essential component of defense in physical combat, which gives them a small evolutionary benefit.
Which Directions do Snakes Move?
There are four kinds of snake locomotion. These movements are called rectilinear, lateral undulation, sidewinding, and concertina locomotion.
1. Lateral Undulation
Lateral undulation is the most common motion among snakes. In this method of locomotion, the snake curls along the body from head to tail. After that, the snake moves forward as some parts of its body straighten. This kind of motion is sometimes referred to as serpentine locomotion.
To make this work, the snake pushes itself forward from a sturdy object, like a rock or a tree. If the snake is on the ground, the snake pushes down where the body bends. It is this downward push that gives the snake “footing.”
As that part of the body is pushed down, the snake moves forward and repeats this same motion throughout the length of the body. Lateral undulation always involves bending.
2. Concertina Locomotion
This motion can easily be mistaken as lateral undulation because they look similar. However, this motion differs in the area of anchoring.
In the concertina locomotion, the snake would reach forward and anchor a part of its body down to the ground. Then, they pull the rest of the body from the back up to the point of the body that is anchored.
After this movement, the snake anchors the bottom part of its body to the ground; then, the snake straightens forward. This motion repeats itself so fast that the whole thing looks similar to lateral undulation.
3. Sidewinding Locomotion
This motion is often seen in rattlesnakes. In this motion, the snake does the same thing as undulation, but also up and down.
If one observes closely, the snake is moving in a specific direction, but its body is perpendicular to this direction. In this locomotion, the head of the snake may be pointing north, but its direction of movement is east.
As the snake undulates its body, it also lifts its body off the ground. In a way, it is like walking and slithering combined into one. This locomotion is also called lateral displacement.
Most snakes that do this live in hot areas like deserts. It prevents them from touching the hot ground. Some snakes also do this in slippery environments.
4. Rectilinear Locomotion
This is a kind of movement where the snake moves in a straight line. In this movement, the snake does not curl its body at all.
It was only in 2017 that this movement was completely understood. It relies on the loose belly skin of the snake. The snake anchors its belly in place and uses this anchor to propel itself forward.
There is one kind of movement that people call slide-pushing. It involves undulation, and the snake propels itself forward by sliding. They typically do this on a smooth surface.
One can observe that if a snake does this, the snake slides widely on the surface. Snakes typically do this when they are startled or alarmed. It is not unusual to see a snake do this if it is trying to escape.
In slide-pushing, the movement is irregular, which is unlike the first four types of locomotion. Here, the snake bends and also presses the tail vertically on the surface at different points. As such, the body slips or slides in a step-like pattern.
Although this locomotion has been observed, not a lot of studies are available to explain it. Scientifically, little is known about the kinds of muscles involved in this movement.
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Conclusion
Snakes can crawl backwards. Although many experts will tell people that they don’t, there are videos proving otherwise. Some may contend that it is really not a movement but rather an illusion. Snakes do not often crawl backwards because they have no reason to. Snakes have several ways to move. These motions are rectilinear, lateral undulation, sidewinding, and concertina locomotion. There is no known case of a snake moving backwards using the sidewinding motion.
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