Pistol Shrimp With a Gun?!

"When in the process of closing its claw, a cavitation bubble is created by a jet of water that is expelled from a socket in the claw."
This is not my observation but the observation of John Roach working for National Geographic magazine. He conducted a study of these shrimp.The video also clearly states this.

 

Were these shrimp actually out of their den foraging for prey, or were they waiting til the gobies got close? I've read studies that stomatopods primarily feed on bristle worms, then another researcher says they rarely eat bristle worms and will only do it if they are starving, so studies aren't always correct.

I didn't say its not a predator at least I didn't mean to. What I meant was the type of predator it is made out to be. In the video doesn't it spot the shrimp from a distance, swim out and kill it, all while using different camera angles and effects?

I know there are a lot of ambush predators with poor eye sight, but the only other fast predator I can think of is bats. Pistol shrimp probably aren't using their claw for echo location, and if they had hearing as good as vision why would they need to pair up with gobies?

If they are such master hunters, I would like to see another video about them. One that isn't so sensationalized. Call me old fashion but I'm a wild America guy. Film the animal from one place, with one camera, interfere as little as possible, and the only effect you can use is slow motion.

posted with tapatalk please ignore bad spelling and grammar

 

The Socket is the 'claw'... just as your finger wouldn't be a finger if you had no socket to move the finger with.

I can see how it can be misconstrued, as water is also in the 'socket' of the claw when the claw is open. As the claw shuts, it is the claw itself that moves back into the socket, displacing the water. The Pistol shrimp did not evolve a separate socket to shoot water with, anymore than I evolved my eye socket to cry with (in both cases, the development of the claw and eye respectively was the primary evolutionary path. 2ndary functions like creating cavitation bubbles and crying would have come along with the main function by happenstance, or been expanded upon after the fact, but are not the intitial primary designs the appendage )

At this point I think we're getting semantical.

Claw Shuts, the antecedent of the 'shot'. Whether we want to argue about the specifics of where the shot starts (claw socket before shutting, or as the cavitation bubble is created at the tip of the claw) seems pedantical.

Either way, the water is being displaced so fast by the intense muscle of the pistol claw, that it creates a cavitation bubble.



Stepho - I hear you, these are not active hunters in the sense of leaving their dens very far... they are more like passive hunters. Imagine you are afraid to leave to your front door for more than 30 feet. Well, you still have a bow and arrow and if a tasty meal comes walking by, you won't mind taking advantage of the situation.

When I feed my Tiger Pistol Shrimp ghost shrimp, it is only the shrimp that wander to the pistol's 1/3rd of the tank that get eaten. He doesn't go crawling to the complete other side of the tank to hunt, but whatever comes near him that he could get is fair game it seems...



He seems to ignore Crabs mostly, I've seen Hermets die as a side effect (their shell being drug down to be used as a functional construction beam, and the hermit is 'discovered' and shot, or just lodged between other construction pieces and can't escape) But any shrimp seem to be his favorite live food (even if more than double the pistols size!!).

He is a scavenger first and foremost unless something wanders into his area, and is very happy grabbing sinking pellets, and frozen meaty foods that sink near him. But losing $50 in Pepperment shrimp in less than 10 days after introducing the Pistol to the tank was lesson enough for me, no more expensive shrimp for me! Not worth the $ risk IMO.


That said, I can get tiny swarms of ghost shrimp to feed him (and to watch cause I like inverts), and even though I can't get nicer display shrimp anymore, the pistol/goby pair is one of my favorite things to watch in the entire tank!

Here's how small he was (just over half inch) when I first brought him home and he ate 5 full grown (2 inch) peppermint shrimp!



You can see how big he is now in a pic on pg 2