Young snapping shrimp’s tiny claws beat underwater acceleration record

Juvenile Big Claw snapping shrimp can grab claws nearly 20 times faster than their parents.Acceleration is similar to a bullet coming out of a gun, even faster than a mantis shrimp

To Catherine Offord

A juvenile shrimp has broken the acceleration record for repeatable body movements in water. Small crustaceans can snap their claws at accelerations approaching 600,000 meters per second, similar to how a bullet exits the barrel of a gun.

This record completely beats well-known underwater species such as adult snapping shrimp and mantis shrimp that use their super-fast claws to hit enemies and ram prey.

Big claw snapping shrimp (alpheus heterochelys) grows to several centimeters in length and has a spring-like mechanism on the larger of its two claws. Previous studies have found that adult shrimp reach claw-snap accelerations of around 30,000 m/s².

Jacob Harrison and Sheila Patek of Duke University in North Carolina wanted to compare juveniles that were only a few millimeters long. They raised some in the lab and used a microscope-mounted camera to video the animals at one and two months of age breaking their claws.

Harrison says that when he tried to shoot at 50,000 frames per second (the frame rate he uses for adult shrimp), the claw motion was still blurry. It wasn’t until researchers increased camera speeds to 300,000 frames per second that they were able to measure how quickly the animals’ limbs moved.

Young shrimp were found to accelerate their claws at 580,000 m/s²This is about 20 times faster than its parent. “These are very high accelerations,” says Harrison.

The entire snap takes just 300 microseconds. The blink lasts about 500 times longer. Few creatures can beat this speed. One exception is the Dracula ant, which can close its jaws in just 23 microseconds. But it’s easier to move quickly in the air than in water. That means the shrimp have to work harder to reach the same speed.

Technically, there is one animal that can pack higher accelerations in the underwater world, but breaks the spring mechanism in the process. A jellyfish shoots a small harpoon at an object, scraping the surface. These spines can reach accelerations about 100 times faster than shrimp claws. However, each one is her one-off, as the harpoon remains hooked to the victim after being shot.

The comparison makes the shrimp’s achievements even more impressive, Harrison said, and the crustacean’s ultra-fast limbs could help researchers design jumping robots and other devices that rely on spring mechanisms. adds that there is “These snapping shrimp have very high acceleration,” he says.