Ferocious, Fearless Mantis Shrimp Is the Honey Badger of the Sea

One of the kung fu film genre’s greatest fight scenes comes from 1979’s Dance of the Drunk Mantis, in which bad guy Rubber Legs channels the raw power of the praying mantis style to deftly tear the pants off our hero Sam Seed, uttering the immortal quip: “Old man, you should be ashamed. Drunk mantis grabs ass.”

Our hero should thank his lucky stars that Rubber Legs didn’t mimic the praying mantis’ oceanic (though totally unrelated) counterpart: the astonishingly lethal mantis shrimp. He would have been dismembered limb by limb with surgical strikes, which would have really mucked up the tone of an otherwise lighthearted movie.

These are the stomatopods, some 550 known species of mantis shrimp that range from less than an inch long to well over a foot. They’re feisty, beautifully complex creatures that strike so quickly that they momentarily superheat the water around their spring-loaded clubs to a temperature nearly as hot as the surface of the sun.

They may not be particularly big, but they will fight just about anything that so much as looks at them funny. Octopuses, humans, each other — you name it. You see, the mantis shrimp doesn’t grab ass. It kicks it.

In da Club

Mantis shrimp are split into two groups. Smashers methodically dismember and knock their prey unconscious. Spearers impale fish with spikey appendages, much like their insect namesake. The speed and power with which these creatures strike simply defies logic. While the spearers can lash at their prey in a mere 20 to 30 milliseconds, the smashers can be 10 times as quick. This is the fastest predatory strike on the planet.

How can so small creature release such energy? “They basically have a spring that they can load using a very forceful but slowly contracting muscle,” said biologist Sheila Patek of Duke University, “and then a latch that releases that energy when they’re ready. And it releases the energy over a really short time period, which means that that appendage comes flying out at really high speeds and acceleration.”

Hemisquilla californiensis, a large burrowing smasher from Southern California. The mantis shrimp’s often vivid colors are thought to play a part in species recognition and in looking fabulous.

Stomatopods manage this strength because invertebrates generally have a more flexible muscle architecture than vertebrates like humans, according to Patek. “This is why when you get pinched by a crab you’re like, ‘What the heck? That’s a tiny little crab,’” she said. “How could that thing possibly generate so much force? And it’s because it has a force-modified muscle that we don’t see in vertebrates.”

With such muscles, the mantis shrimp can launch its clubs at 75 feet per second — through the resistance of water, no less. Such speed generates an area of low pressure that forms vapor bubbles in a process called cavitation. When these collapse, they release tremendous energy in the form of, oddly enough, light and heat, an incredible 8,500 degrees Fahrenheit. (Although no one has ever measured the temperature of a mantis shrimp strike, according to Patek other measurements of cavitation’s heat release can be reliably applied to the punch.)

This searing heat is too fleeting to fry the prey, but that’s no consolation to the poor critter. The shock wave from the implosion of bubbles follows the punch and slams into the stomatopod’s target, often knocking it out cold. Keep in mind that this is happening with a pair of clubs, bringing the total impacts in each strike to four.

In this manner the mantis shrimp can smash through even the most mightily armored clams and snails. As for crabs, it’ll cleverly blast off their claws first, then amputate the remaining limbs to immobilize it — if it isn’t already unconscious, which would be a pretty merciful exit, all things considered.

Patek is trying to figure out whether stomatopods have some measure of control over cavitation. The phenomenon can only happen in certain conditions — typically warm, low-pressure waters, which these creatures happen to call home. According to Patek, their strikes cavitate without fail.

“Is there anything about their appendages that allow them to wield cavitation bubbles effectively or not, or is it just simply an accident of just moving fast?” Patek asked. It could well be that the mantis shrimp has evolved to weaponize bubbles.

Now, boating enthusiasts are all too aware of the destructive power of these cavitation bubbles. The same phenomenon happens to propellers as they slice through the water, eventually wearing away the metal so badly that you must buy a replacement. Or a whole new boat if you’re baller like that.

So how do mantis shrimp not eventually wear their reinforced clubs down to the muscle? Well, they do, but as arthropods, every so often they molt, and are afforded the opportunity to build up a brand new club. This molting period is a highly vulnerable time, what with their as-yet unhardened clubs blowing to pieces if they strike something. So they’ll dance a little jig, waving their appendages around and pretending to strike. It’s a bluff. I don’t know about you, but I’d never call them on it, though.

The Eyes Have It

Behind this incredible method of hunting are the animal kingdom’s most complex eyes, peepers so amazingly evolved that their sophistication seems damn near unnecessary. (That’s me being hyperbolic. They’re anything but unnecessary, of course. Animals don’t just waste energy and resources building worthless features.)

As with bees or flies or crabs, they are compound eyes, but unlike those creatures, mantis shrimp “have a very unusual adaptation in that multiple parts of the same eye view the same point in space,” said biologist Tom Cronin of the University of Maryland, Baltimore County, “which is sort of like having multiple eyes in one, in a way.” Whereas we use two eyes to judge distance, mantis shrimp can do that with a single eye.

Some mantis shrimp species also have the most complex set of color receptors of any animal on Earth, a total of 16 classes compared to our measly four (interestingly, though, half of all stomatopods can’t detect color at all). Their often wild coloration combined with these highly developed powers of color-detection aren’t accidents — they’re likely key in species recognition. You’d hate to try to mate with the wrong species and get a club to the face for your efforts.

On top of that, some mantis shrimp can see a variety of colors in ultraviolet, so “they’re seeing colors that no other animal can see, in a sense,” said Cronin. “Basically color is a property of the nervous system so it’s not really present in the real world, but they can see aspects of the ultraviolet that nothing else can see.”

Lysiosquillina lisa, a burrowing spearer from Indonesia, is named after the Mona Lisa. See the resemblance? Yeah it’s not really named after the Mona Lisa.

That’s right: Colors only exist because your brain thinks they do. Your noodle is simply assigning a color to a wavelength of light collected by your retina. Same goes for the mantis shrimp with its ridiculous variety of photoreceptors. (It’s a polychromatic philosophical nightmare, really. What if a mantis shrimp had synesthesia, a human brain disorder in which sounds can produce the experience of color? They’d be freaking out, man, but not really because their brain would perceive it as normal reality. It’s … complicated.)

Anyway, in addition to all of these visual superpowers, the mantis shrimp is the only known critter to see circular polarization of light. Linearly polarized light — the glare off windows and such that’s neutralized by those expensive polarized sunglasses you lost recently — is common, but the circular type is quite rare.

“It’s only created under very special circumstances,” said Cronin, “and the only thing we know about it for sure with the mantis shrimp is that they use it for signaling, so they themselves produce patterns that are circularly polarized on their bodies, which is extremely odd.”

It’d be easy to assume that this staggering amount of information would require an enormous brain to handle, but this is not the case with a mantis shrimp. Whereas our eyes funnel raw data to the brain, in stomatopods the bulk of the processing is done in the eye itself. Indeed, the mantis shrimp’s eye is actually larger than its brain, which if you think about it would look crazy weird if humans were the same way.

“By having all of this complexity at the receptor level,” said Cronin, “you basically are preprocessing everything. So that when it leaves the receptors it’s already streamed into information channels and the brain just basically says, How much is there of this, and How much is there of that, and Make a decision based on that.”

All this data and processing power is pivotal when hunting with such speed and strength, or when defending yourself, for that matter. These things are seriously ornery, like the honey badgers of the sea, and the more information they have to work with to push back against large predators like octopuses, the better.

If you were a mantis shrimp, this photo would definitely be NSFW, if catch my drift.

Mantis Shrimp Falling in Love and Wrecking Homes

The mantis shrimp has certainly had plenty of time to evolve the planet’s most impressive eyes — stomatopods split off from other crustacean stock about 400 million years ago. That’s truly ancient, considering that while life has been around on Earth for almost 4 billion years (or 6,000 years, depending on your math), lifeforms we’d recognize as animals only showed up some 570 million years ago.

Early stomatopods began with a single simple spiked appendage, and have since evolved into the spearer-smasher dichotomy. Smashers tend to keep to preexisting burrows under rocks, which they will fight each other for, while spearers actively burrow into sand to ambush fish swimming above, with some smaller species even swimming up the water column to grab plankton. And without the powerful weaponry of the smashers, spearers will abandon a burrow if challenged and just dig a new one.

Surveying the scene outside their burrow, the smashers can emerge in a flash and “certainly can take shrimp and crabs, even fish, and disable them with a single strike,” said marine biologist Roy Caldwell of the University of California, Berkeley. “Then they almost always will bring the body of the prey back to their cavity and process it and break it up into pieces and pull out the meat.”

Interestingly, in one group of spearers, burrows are actually shared — by a couple in the stomatopod version of love. “They’ve evolved monogamous mating systems,” said Caldwell, “and pairs form and spend a lifetime together, which can be 30 to 40 years.” The males do the hunting, catching a fish for themselves and the next for the female, while she digs and lays eggs.

Indeed, their sexual dimorphism — physical differences between males and females of a species — reflects this. Males in this monogamous dynamic are more powerfully built, though this doesn’t excuse them from parental duties. In some such species the female will actually lay a second clutch of eggs for the male to schlep around, effectively doubling their number of potential offspring.

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