Full Breakdown
Dwarf Reed Snakes Roll Away from Threats in a High-Speed Cartwheel
By Drooid · · How we work
Core Event: Laboratory Confirmation of a Rolling Escape
Researchers from Japan’s Toho University captured the first systematic video evidence that dwarf reed snakes (*Pseudorabdion longiceps*) can propel themselves by cartwheeling across a flat surface. In a 2.2-meter racetrack, snakes were gently tapped to move forward while overhead and side cameras recorded their motion. All *Pseudorabdion* specimens rolled, reaching speeds of 1.7–3.7 m/s (? 6–13 km/h). Six *Calamaria* reed snakes placed on the same track did not exhibit the behavior.
Background & Context: From 19th-Century Tales to Modern Observation
The phenomenon echoes 19th-century naturalist descriptions of “hoop snakes,” once dismissed as fanciful. A 2019 sighting in Sarawak, Malaysia, of a “very weird” rolling movement prompted the Toho team to collect eleven *P. saravacense*, one *P. collaris*, one *P. longiceps*, and six *Calamaria* snakes from Kubah National Park, where the tiny reptiles hide under leaf litter.
On-the-Ground Reports
Field researchers noted that the snakes measured only 11–28 cm in length and were difficult to locate because “they always hide under the leaves,” said Y. Kojima, an ecologist at Toho University. The 2019 mountain-road sighting provided the first real-world confirmation that the behavior was not limited to the laboratory.
Data & Statistics
- Size: *P. longiceps* adults are 17–23 cm long; other *Pseudorabdion* species range from 11–28 cm.
- Speed: Rolling speeds of 1.7–3.7 m/s (? 6–13 km/h).
- Track Width: Snakes negotiated a path only 20 cm wide while maintaining the rolling motion.
Official Statements & Responses
Yosuke Kojima emphasized the difficulty of field collection, noting the snakes’ habit of concealing themselves beneath leaves, and remarked the team was “quicker than them” in coaxing the snakes onto the racetrack. Jessica Tingle, a biologist at Brown University, expressed curiosity about the evolutionary origins of the movement and whether the snakes possess unique anatomical or neural adaptations.
Why It Matters
The study shows that even diminutive, nocturnal snakes can evolve specialized locomotor strategies when faced with predation. By keeping the head oriented forward while the body loops, the snakes preserve sensory awareness during rapid escape, challenging the assumption that snake locomotion is limited to slithering.
Conflicting Reports & Gaps
Two sources provide differing speed estimates: the laboratory data report 1.7–3.7 m/s, whereas a popular-science article cites roughly 0.3 m/s. The discrepancy may stem from different measurement methods or definitions of “speed” (peak versus average). While all *Pseudorabdion* species rolled, the behavior was absent in the closely related *Calamaria* snakes, leaving open questions about the precise anatomical or neural traits responsible.
Verbatim Quotes
- “They always hide under the leaves,” — Y. Kojima, ecologist, Toho University
- “I am very curious how such a strange and possibly demanding movement evolved … whether dwarf reed snakes have something special in their anatomy, physiology or neural control that lets them do it when their close relatives apparently can’t or don’t,” — Jessica Tingle, biologist, Brown University
- “Some writers in the 1800s talked about ‘hoop snakes’ and described their motion as rolling, but that seemed pretty fantastical to me, and I chalked it up to overly inventive imaginations,” — Jessica Tingle, biologist, Brown University