“To capture prey, chameleons ballistically project their tongues as far as 1.5 body lengths with accelerations of up to 500 m s–2. At the core of a chameleon’s tongue is a cylindrical tongue skeleton surrounded by the accelerator muscle. The key structure in the projection mechanism is probably a cylindrical connective–tissue layer, which surrounds the entoglossal process… This tissue layer comprises at least 10 sheaths that envelop the entoglossal process. The outer portion connects anteriorly to the accelerator muscle and the inner portion to the retractor structures. The sheaths contain helical arrays of collagen fibres. Prior to projection, the sheaths are longitudinally loaded by the combined radial contraction and hydrostatic lengthening of the accelerator muscle, at an estimated mean power of 144 W kg–1 in C. melleri. Tongue projection is triggered as the accelerator muscle and the loaded portions of the sheaths start to slide over the tip of the entoglossal process. The springs relax radially while pushing off the rounded tip of the entoglossal process, making the elastic energy stored in the helical fibres available for a simultaneous forward acceleration of the tongue pad, accelerator muscle and retractor structures. The energy release continues as the multilayered spring slides over the tip of the smooth and lubricated entoglossal process… Thus, we have identified a unique catapult mechanism that is very different from standard engineering designs…” (de Groot & van Leeuwen 2004:761)