A pistol shrimp’s claw can make a sound by shaping a burst of water.
When the claw closes quickly, it drives a narrow, fast jet into the surrounding water. The flow can spin into a vortex and drop in pressure, forming a cavitation bubble—a pocket of vapor in the liquid. As that bubble collapses and rebounds, it sends out sharp pressure pulses.
Researchers modeled the claw’s motion and compared their approach with earlier experiments to investigate how the bubble forms. The snap can help the shrimp hunt or communicate, but the important trick is physical, not magical: a small animal turns a fast movement into a brief event in the water around it. The surrounding fluid becomes part of the shrimp’s signal and tool.