A French team measured water transit through the trap at 30 to 60 seconds, far too slow to explain a sub second closure. The replacement mechanism is closer to a sprung trap than a hydraulic one, and the molecular chain that fires it remains unknown.
A Venus flytrap's clap is not a hydraulic event. It is the release of elastic energy that the leaf has been quietly storing, fired by a signal that propagates across the plant in a fraction of a second. That is the upshot of new measurements from a French team led by Yoël Forterre at Aix-Marseille University, reported by New Scientist on 11 June 2026. The work does not finish the puzzle Charles Darwin opened when he began studying the species. It does, however, displace the dominant explanation for one specific part of it: the speed of the snap.
For most of the last century, the textbook account has been hydraulic. Touch the trigger hairs twice in quick succession, and the plant is supposed to pump water from one side of the leaf to the other, shrinking the inner surface and swelling the outer one, curling the trap shut. The story is elegant and intuitive. It is also too slow.
Forterre's group directly measured how long water actually takes to transit the trap, both through individual cells and through the tissue as a whole. Their result, reported in New Scientist, was 30 to 60 seconds. A real closure happens in well under a second. Water redistribution on that timescale cannot account for the motion. The hydraulic model is not just slow. It is off by one and a half orders of magnitude.
So what does the closing? Forterre's proposed alternative is closer to the engineering of a sprung trap than to a living pump. In the resting state, the leaf is held in its open, concave shape by internal stresses in the tissue. After a valid trigger, the outer epidermal cell walls soften, releasing that stored stress, and pressurized inner cells expand against the now-pliant outer layer, lengthening the outer edges and bending the leaf shut. The geometry of the leaf, primed and waiting, does the work. The trigger is the release, not the cause of the motion.
The trigger itself is fast enough to fit. Two touches within a short window fire an electrical signal and a wave of calcium ions that sweep across the leaf, reaching distant cells within a fraction of a second. Plants do not have neurons, and the analogy to a nervous system overclaims, but the propagation speed and the use of calcium as a carrier make it a genuine non-neural signaling system. What it does once it arrives is the open question.
Forterre is direct about the boundary of his own result. As he told New Scientist: "We understand the beginning of the chain of events, touch sensing, and the end, trap motion, but the molecular link connecting the two remains largely unknown." The molecular identity of the chain that links a calcium wave to a sudden change in cell-wall stiffness is exactly the kind of question the new mechanism makes urgent. Until that link is in hand, the model describes the start and finish of the snap but not, in any chemical sense, the middle.
Not everyone in the field is ready to retire the older model. Sergey Shabala at the University of Western Australia is the named skeptic in the New Scientist report. He argues that water movement could in principle be simultaneous across many cells rather than consecutive, and that a softening of cell-wall stiffness would plausibly take several minutes rather than fractions of a second, meaning the new work "does not explicitly rule out" the hydraulic account.
Forterre's team pushes back with measurement. They did not infer swelling times from theory; they watched pieces of trap tissue swell. The directly observed swelling was slow, consistent with the 30-to-60-second water transit. And the loss of cell-wall stiffness, when they measured it, was, in their words, "surprisingly rapid." The dispute is genuine and worth tracking. It is also a useful one to have in the open: a long-standing model is being tested on a quantitative timescale argument, and an independent expert is contesting the test.
The reason the dispute matters beyond botany is that the flytrap sits at the intersection of plant physiology, soft-matter physics, and the engineering of fast-moving structures built from living tissue. A mechanism that depends on stored elastic energy and a trigger that releases it is a different design principle from one that depends on bulk water transport. The first invites comparisons to pre-stressed composites and to soft-robotic actuators that switch state when a material threshold is crossed. The second invites comparisons to plants that move by swelling. Choosing between them changes which analogies are productive.
There is also a small piece of honest bookkeeping to do. The Venus flytrap's snap is the part of its behavior that most looks like an animal reflex, which is why it has anchored the popular imagination since Darwin. But the snap is one of at least four questions folded into the species' puzzle: how it senses, how it closes, how it digests, and how it reopens. The new mechanism addresses the second. The first remains a signal-propagation problem. The third and fourth are separate, slower problems of secretion and growth. Reporting the work as a solved mystery is a mistake. Reporting it as a faster, more carefully measured mechanism that displaces a slower one is accurate, and is the version of the story worth following.
Watch next: the Forterre group's primary paper, which the New Scientist piece summarizes but does not link directly in the available text, and the Shabala group's response, when it comes. The timescale test is concrete enough that it can be replicated. If it holds, the hydraulic model for the flytrap's snap is finished in practice. If it does not, the dispute is the opening move of a longer argument about how a plant can move faster than its own water.