Despite having a powerful punch, mantis shrimp don't want fight their way out of a conflict.
In fact, when facing down another mantis shrimp, the dispute is often settled through a series of thought processes and communication "phases" instead of trading blows. And that's a good thing for both fighters, since mantis shrimp pack a wallop of a punch.
Fighting for turf
How animals settle things without killing one another — which ultimately isn't good for the survival of the species — has been a subject of debate among scientists. Is it based purely on size? Is it based on actual, albeit limited, fighting? Is there an internal process by which one of the fighters knows it will lose and thus never even fight?
To figure out how the mantis shrimp decide who wins, researchers at Duke University pitted mantis shrimp against one another in battles over artificial burrows made of plastic tubing. One shrimp was allowed to make the tubing its home, and then researchers introduced a rival of the same sex to the tank to see how the shrimp decided who got to keep the burrow.
In the first phase, the shrimp would either flick their antenna at their foe, picking up its scent, or raise its body up a bit and wave its mighty folded forelimbs around a bit. If this didn't discourage one of the fighters, a second round would begin. This phase involves a bit more violence, but there still isn't an actual fight; it's more like controlled sparring, as the researchers called it. Using their forelimbs, the shrimp will strike one another on the tail, which is armored, in a ritualized manner.
Both of these phases involve the shrimp basically sizing each other up and figuring out if they stand a chance against their opponent. If one shrimp decided it had a chance, it would shift to a sparring phase, and the shrimps would trade actual blows. If things got to that point in the fight, researchers noticed that the fight would rarely shift into a previous phase. The sparring would decide the winner and the loser, and the loser would often be allowed to run away from the fight.
Of the matches the researchers staged, if the mantis shrimps were each roughly the same size, the fights ended in sparring matches almost twice as often than matches with mismatched body types. In the mismatched fights, the smaller of the shrimp would flee before a sparring match could start.
"Our results reveal that animals with deadly weapons can use them to assess relative ability and resolve conflict safely," the researchers concluded in their study, published in the journal Proceedings of the Royal Society B.
Settling things safely is important for the mantis shrimp's continued survival. Their punches are capable of breaking glass and snail shells alike, with a force of 1,500 Newtons, or about the force generated by a 340-pound object crashing into something. (Mantis shrimp, let alone their claws, do not weigh that much.)
Additionally, their blows are incredibly swift, snapping out with an rate of acceleration that matches a .22 caliber bullet. Should the shrimp somehow miss its prey with a strike, well, don't worry, those fast-moving claws also create pockets of air in water that, when they implode, create enough force to stun in the intended victim.
All this means that a fight between two mantis shrimp would not only be incredibly vicious, but it would also be very bad for both parties. It's unlikely that either combatant would scuttle away from the fight without some wounds, leaving both vulnerable to other predators, if not dying from the wounds outright.
You may see a level of diplomacy involved in this dance, but it's simply a safe way to settle differences that allows the species to survive.