For a flat sea creature just a few millimeters across, a gentle poke is instantly recognized as danger. Trichoplax adhaerens—a translucent blob with no head, brain or muscles—scuttles away in seconds when touched. Imagine a flattened multicellular amoeba moving as a single unit: Trichoplax is only ~20 microns thick and a few millimeters wide. It glides on surfaces by beating tens of thousands of cilia on its lower epithelium (the underside), like microscopic oars dragging against the water.
Yet unlike most animals, Trichoplax has no obvious front or back end, no nerves or muscles at all. How can such a simple “crawling carpet” steer or change direction without a brain?
A new study reveals the remarkable flexibility of this pinhead-sized animal. While in most creatures, the orientation of each cilium is fixed early in development and locked to the body’s axes, Trichoplax achieves its swift escape by reorienting its thousands of hairlike cilia.









