Snapping shrimp close their claws so quickly, they create shock waves. This video reveals how they do it

Less than 10 centimeters long, the few dozen species of snapping shrimp may not look like formidable foes. But their lightning-fast claws close so quickly that they make sounds louder than a gunshot, and create shock waves in the water that stun fish, worms, and other prey. But the evolutionary steps from simple pinching to ultrafast snapping were a mystery to scientists. Now, a team of biologists has closely examined the claw anatomies of 114 species of shrimp, including about a dozen known snapping species. As they report in Current Biology, they found two new types of claw joints heretofore unknown to science. The first was a simple slip joint—common in many pocket knives—in which a tiny ridge helps keep the claw open until enough pressure snaps it closed. This allows the claw to close a bit faster than usual. The second was an even further modified version called a cocking slip joint, where the ridge fully cocks the claw open. That allows snapping shrimp to build up incredible tension in the claw’s muscles before a secondary muscle movement releases it, slamming it shut at ultrafast speeds and generating a shock wave. Now who are you calling “shrimpy”?