By: Phoebe Shi

The US Army is now using the calls and sounds of aquatic creatures like goliath groupers and pistol shrimp as sonars to detect underwater predators. Current sonar methods can be harmful to animals like whales. Whales use their own sonar which, when combined with our sonars, can confuse the whales and cause them to end up stranded on the beach.

Pistol shrimp, also known as snapping shrimp, are a type of shrimp used as underwater sonars. Pistol shrimp’s incredibly loud snaps are created when they close their pincers so quickly that the vacuum bubble they create pops and lets out thousands of degrees of heat. When there are multiple shrimp snapping, they can work like the artificial sonar pings the army uses. To use the shrimp in this way, the army must track the sound, then track what the sound is reflecting off of.

Goliath groupers are also a species of fish being used as sonars. These fish use extremely loud and low-frequency calls to scare off predators. The calls can be heard from 800 miles away. Not all calls are used for defense though; some are used to attract mates.

Laurent Cherubin is one of the head researchers of the ‘Grouper Guard’ team. This team uses algorithms that have been trained to be able to tell the difference between grouper calls. The algorithm is then put into hydrophones (underwater microphones), which are put into coral reefs. The team tracks the groupers and is able to also track the predators.

Using these creatures to detect submarines and predators represents a step up from using the harmful artificial pings and sonars we used before.