Can a supersonic boom stun a person

Pistol crab - subspecies and their way of life

The pistol crab is a crab from the Alpheidae family that produces a powerful sound. The Alpheidae are crustaceans. Snapcocks have a large claw. The very loud soundthat they give off can stun or even kill prey or keep predators away.

Examples of pistol crabs

Examples of gun crayfish are the following species:

  • Alpheus heterochaeliswho have favourited Bigclaw Snapping Shrimp, a shrimp a few centimeters in length and green color. The loud claw can be left or right, its size can reach almost half of the body. This shrimp lives in the western Atlantic. Researchers have studied how this shrimp could produce such a sound. It turned out that that fast closing the claw causes a jet of water to be emitted at high speed, creating a pressure differential that implodes a bubble; it is the implosion of this vacuum bubble that creates the sound of more than 200 dB. The water at this point can exceed temperatures of 4,000 ° C,
  • Alpheus dentipes, the Mediterranean shrimp, which has a sting on its legs P3 and P4: This species found in the Mediterranean measures around 3 cm,
  • Synalpheus pinkfloydi, a pistol shrimp with pink tongs, hence the Pink Floyd-inspired name. This shrimp was found off the coast of Panama in the Pacific Ocean.

Pistol crab claws make the loudest sound in the world

The loud bangs of the pistol shrimp shooting are created by their claws. Like other shrimp and crayfish, they have armored hulls. On the head there are two scissors. These are divided into base link and scissor finger.

The claws can make up up to 50% of the body weight of a pistol crab, and one of the two claws is often greatly enlarged in males.

In some species armor and scissors are heavily calcified, like a lobster. Often, however, they are also in a transparent body shell that lets the organs shine through. Still others glow in color.

Which of the two scissors is the “pistol”, ie whether it is left or right, is different. But there is always only one “pop scissors”. Interesting: If the crackers lose their “pistol”, the other pair of pliers is converted into a shooting device. A normal gripper grows back where the original “pop scissors” were.

This is how the “bang scissors” of the pistol shrimp work: The Scissors are opened and the resulting cavity fills with water (the pistol is loaded). A pressure piece, which is also located on the scissors, compresses the water so strongly when it snaps shut that it is forced out explosively.

This is how the cavitation bubble works

When the water shoots out due to the strong pressure, a so-called cavitation bubble forms, which is filled with steam. That means: The great energy that the shrimp has exerted through the pressure on the water transforms the water into a shooting bubble of steam. Due to the fast speed negative pressure is created. When this low-pressure vapor bubble implodes, the deafening bang is generated, which is even louder than a jet.

The cavitation bubble is not only fascinating because of the noise. In addition to the bang, 2 other things happen: warming and light.

The bang flashes for a brief moment. Call researchers this "sonoluminescence" and thus describe that light is generated from sounds.

In addition, the rapid vapor generated in the cavitation bubble is so hot that a temperature of over 4,000 ° C is measured in its vicinity.

This entry was posted in Fauna, Wiki by Bernard Miletic. Permalink