Scientists Crack the Secret of Venus Flytrap's Speed

Charles Darwin spent years puzzling over how the Venus flytrap snaps shut its jaw-like leaves so fast; now, a French team says it has the answer. In a study published in Science, physicist Yoël Forterre and colleagues report that when an insect brushes the plant's tiny trigger hairs, cells on the trap's outer surface rapidly soften by 30% to 40%, per the Guardian. This swift change in stiffness lets the curved leaf bend into a closed position in under a second, much like a rubber popper toy turning inside out.

Using dental glue to hold the traps perfectly still and a metal tip to poke and measure the leaf's resistance, the team found the effect stems from the cell walls becoming more flexible, not from water swelling inside the leaf as long suspected, per Smithsonian. That process took far too long—30 to 150 seconds—to account for the snap, which Forterre tells Reuters "can occur in as little as one tenth of a second." The work helps explain how a plant with no muscles or nerves can act like a sprung trap—and reveals a level of mechanical control Forterre says he hasn't seen in any other plant. "Plants are known to modify the mechanical properties of their cell walls during growth, but the Venus flytrap appears to push this mechanism to an extreme," he says.