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Gobies With Shrimp Photo Courtesy Jan Derk/Snapping (Pistol) Shrimp Photo Courtesy Scubadiving.com
They operate their ‘gun hand’ just like they’re holding one, and that is how they became called pistol shrimp. To scientists they are snapping shrimp, or Alpheus heterochaelis. The way these ambush predators operate is nothing short of amazing. Watch this little video to better understand how they do this.
These small animals have very poor eyesight, say the researchers. Gobies will live with them outside their burrow. If predators come near, the gobies will sound the alarm before scurrying to hide. This lets the shrimp know to not come out for awhile. Years ago scientists studying these cute little finger-size shrimp finally were able to figure out the source of the loud bang and the method of stunning prey works. The team revealed the shrimp compresses a bubble in its ‘boxing glove’ arm. The bubble emits not only a sound, but the team was startled to discover it also emits a flash of light, which they further learned has a core temperature hotter than the sun!
This little shrimp prowls all shallow water tropical sea floors in search of food. One of their favorite foods is cleaner shrimp (mentioned in a past posting) but they also eat crabs. The shrimp are dark green in color and have two claws, one is much larger than the other. When their claw snaps shut a jet of water shoots out at 62 miles per hour, generating a low pressure bubble in its wake. The bubble collapses with a loud bang when the pressure stabilizes. The research team found out, through recording this process with high speed cameras, time involved is only 300 microseconds. They explain the flashing phenomenon as similar to sonoluminescence, i.e. bubbles that are in liquid driven by a strong sound field emit light. They nicknamed this shrimp weapon use “shrimpoluminescence”.
Will the snorkeler in Hawaii see this animal? Probably not, but you will most definitely hear them using their technique. The ocean is a noisy place with marine mammal communications, fish conversations, and the ‘frying bacon’ sound of the snapping shrimp working hard to collect a meal.
