A brown snake with blue streaks curled on a orange leaf.

The dwarf reed snake is often found in the leaf litter of southeast Asian forests. Image © Evan Quah.

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Snake that cartwheels away from predators described for the first time

A secretive snake may use cartwheels to escape from predators.

The dwarf reed snake uses the unusual behaviour to startle potential threats, before using a burst of speed to disappear into the undergrowth.

Researchers in Malaysia have discovered a new way that snakes can move.

While snakes are known to slither, jump and even glide, no snake has ever been seen cartwheeling before. But a new study reveals that, when startled, Pseudorabdion longiceps throws the coils of its body into a loop, catapulting itself through the air before rolling forward.

Though there have been anecdotes of the species' unusual behaviour before, this paper is the first time it has been scientifically documented.

Dr Evan Seng Huat Quah, the lead author of the study published in Biotropica, says, 'I had observed this behaviour once in passing previously but did not have the equipment at the time to record it.'

'When we came across the snake highlighted in this study while conducting herpetological surveys for other species, we were thrilled. This allowed us to use our camera gear to successfully capture cartwheeling behaviour.'

Dr Ian Brennan, an expert in reptiles at the Museum, adds, 'This cartwheeling is a pretty amazing behaviour, and what's most peculiar about this is that it is repeated.'

'It's not just a single motion to startle a predator, which a lot of different animals do, but also an intentional movement by the snake to fling itself away from a threat.'

Three photographs of the dwarf reed snake at different stages of the cartwheel.

The cartwheeling behaviour appears to be the combination of jumping and startle behaviours, allowing the snake to evade predators. Image © Evan Quah.

How does the snake cartwheel?

Having no limbs, snakes have to cartwheel somewhat differently than humans.

The dwarf reed snake curls its body into an s-shape before using its tail to launch itself off the ground. In the air, its body loops forward as the head touches the ground. The tail then comes over the head as the snake rolls forward onto its body. This cycle then repeats to keep the snake moving.

'There are a few similar behaviours in other animals, but nothing quite like this,' Ian explains. 'For example, there are legless geckos called pygopods which throw their body into a sine wave and use their long tails to spring off the ground, which is a bit similar to how these snakes cartwheel.'

'There are also small jumping vipers which use their tails to spring off the ground.'

Though cartwheeling may not seem like the most practical way of moving, it's effective. The 25-centimetre-long snake can cover six times its body length (1.5 metres) in just five seconds, allowing it to dash away from any potential threats.

It also is thought to minimise the amount of scent left behind on the ground, making it harder for any pursuer to follow.

The trade-off for this burst of speed is the energetic cost of cartwheeling. As the process uses the contraction of muscles across the snake's body, it's not something it can keep up forever.

'Cartwheeling appears to be very metabolically taxing for the snake as they cannot sustain this behaviour repeatedly or over long distances,' Evan says. 'It is a defence mechanism employed only under extreme duress.'

To mitigate this, the dwarf reed snake can make use of downhill slopes to help it roll. This can give it a quicker start, as well as keep the cartwheeling going for longer.

Most other animals which roll also use hills, although tend to let gravity do the work rather than putting additional effort in like the snake. Animals including pangolins, pebble toads and wheel spiders are all known to get away from threats by rolling down slopes.

A black toad sits in a rock crevice.

The pebble toad tucks itself into a ball and rolls down hills to escape from predators. Image © Gérard Vigo, licensed under CC BY-SA 3.0 via Wikimedia Commons

What are reed snakes?

The reason that this behaviour has probably not been scientifically documented before is because of how little is known about reed snakes. While they're very common in their habitats, their size and lifestyle mean they're not always seen.

'Reed snakes are semi-fossorial, secretive and generally nocturnal,' Evan says. 'They usually hide in the leaf litter or beneath logs, sand, and rocks, making them hard to detect.'

The difficulty in finding the snakes means that while there are many different species of reed snakes, they're relatively understudied. As well as being important in their own right, they are also prey for other animals including monitor lizards, birds and even other snakes.

The dramatic reaction of reed snakes to these predators means that it's very likely that people living in the area have seen this behaviour before now, but that information hasn't filtered through to the scientific community.

'Local communities or Indigenous People know many things about their local flora and fauna, but that hasn't always been valued scientifically,' Ian says. 'This means there could be lots of behaviours that haven't been written about yet, and that's exciting.'

Evan hopes to improve the state of research surrounding the reed snakes, and their cartwheeling behaviour, in his future work.

'At present, there is no other species of snake formally recorded as using cartwheeling as a defence mechanism, but it may be more widespread in relatives of the dwarf reed snake,' Evan says.

'There are anecdotal reports of other species performing this behaviour including another member of the same genus, Pseudorabdion albonuchalis. I hope to see just how common cartwheeling actually is.'