When it really comes down to it, what humans have over other animals is range. We can’t wrestle bears and any attempt to go boxing with a kangaroo would end extremely poorly. But what we do have is rocks, and spears, and guns. Why fight when you can shoot? And, for the most part, we’re alone in this ability. But not completely. There are spiders that throw webbing and spitting cobras. There are archer fish that can snipe insects out of the air. There are even shrimp that have turned one of their limbs into a shotgun.
To tell the truth, I first heard of pistol shrimp for a completely different reason. Some species have a symbiotic relationship with goby fish – the shrimp digs a burrow, which the two species share, and in return the goby uses its superior eyesight to watch for predators. Now, the two species do make a cute couple, but any other species of fish should be wary because the pistol shrimp has no qualms about hunting its neighbors.
Its weapon is the aforementioned limb. The specialized claw is large, monstrously large – it’s nearly as thick around as their bodies – and with its heavy, recurved pincers looks more like some sort of industrial cutting tool than a limb. However, the claw isn’t used to cut or hold prey.
The claw is specially built to close incredibly quickly, in less than a millisecond, shooting out a small jet of water at over 100 kilometers per hour. The jet is immediately followed by a low-pressure bubble in the water. It’s this bubble that really does the damage. When this bubble collapses it creates a shockwave louder than a jet engine, over 200 decibel, and producing a temperature flash of over 5000 Kelvin. Anything close to this blast is stunned, if not immediately killed. You can see an example of this behavior in the video below.
Luckily, the kill-range is not very long, but the sound is loud enough that it can disrupt navy sonar and can even drown out whale song. Impressive for such a little guy.