Mantis Shrimp Can Punch Each Other to Death But Prefer to Resolve Conflicts Peacefully

When an argument comes to blows, it’s especially devastating for a mantis shrimp. Their punches are powerful enough to break glass, so if they fight among themselves, a disagreement could be fatal.

But a new study shows that mantis shrimp communicate without trying to kill each other.

Scientists at Duke University decided to create some conflict between mantis shrimp in order to see if and when they would resort to drastic violence to solve it. They took pairs of mantis shrimp of a certain species, Neogonodactylus bredini, and gave one of each pair a burrow. Then they sent the other to the area to see if they would fight over the burrow.

Mantis Shrimp Eyes Mantis shrimp have a punch strong enough to break glass, boil water and kill each other. Michael Bok/University of Lund

The mantis shrimp didn’t immediately deploy their powerful weapons to knock each other into the next world. Instead, they went through several phases of communicating to demonstrate how fit they are—and why they’re formidable opponents.

First, they flicked their antennae. Then, they raised up the front of their body to show off. If neither animal left the ring, they sparred by nonlethally tapping each other on the hard shells on their back.

"These 'phases' are indicative of how they are assessing each other," Patrick Green, an author of the study, wrote to Newsweek in an email. Green is a biomechanics researcher at Duke University.

After they had assessed who was the fitter contestant, one mantis shrimp would move away from the burrow, and to the victor goes the spoils. The research was published Wednesday in the journal Proceedings of the Royal Society B.

Why didn’t the mantis shrimp punch their opponent to the death? Non-lethal displays are common in the animal kingdom. This behavior communicates that an individual has plenty of resources and could harm their opponent, so the opponent might as well just back off. It’s a good idea, evolutionarily speaking, for the smaller, weaker individual to take a hint and live to try again later.

Furthermore, killing and maiming members of your own species isn’t a good survival tactic for a population. That’s why fights for mates involve locking horns, but not goring each other. Even if you win a fight and kill your opponent, a full-fledged bout of violence is likely to leave both participants damaged.  

However, if you are the prey of a mantis shrimp, you aren’t likely to receive this type of communication. They’ll go straight for the kill. Mantis shrimp can move their appendages as fast as a speeding bullet, and their strength is enough to break glass and boil water. Luckily for smaller members of these rainbow, aquatic creatures, conflicts within the species rarely come to blows.  

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