These technicolor murder machines are called mantis shrimp and they might just be the coolest animal in the entire ocean, and I don't say that lightly.

And if the speed of their clubs of up to 31 meters per second isn't impressive enough, the acceleration of those clubs rivals the acceleration of a bullet being fired from a gun.

For a human to break the same shells that a mantis shrimp breaks, we would need a big hammer and a strong swing.

A mantis shrimp can achieve the same thing with an appendage smaller than a small child's pinky finger.

These guys help make up an entire category of the natural world that's only been recently described, the ultra-fast.

Forget about the fastest human or even something like a cheetah, those don't even register on the ultra-fast scale.

Instead, it's populated by extraordinarily fast creatures such as trap-jaw ants, launching fungal spores, ballistic termite jaws, and stinging jellyfish.

Fishers working around shallow reefs have attested to the damage a mantis shrimp can do to their bare hands and feet, and aquarium owners have to be especially careful not to annoy their powerful little friends.

These guys can sometimes punch through extremely thick glass and will decimate any other animals living alongside them in the tank.

These wily fighters are among the most ferocious carnivores in the ocean, and yet, curiously, the fastest species among them prey almost exclusively on the slowest creatures, like snails and oysters.

And the slower species go for the fastest prey, snatching creatures two or three times their size from crabs to octopuses.

And not only are mantis shrimp extremely fast at punching and stabbing, their eyes are the most complex in the entire animal kingdom.

Whereas humans have three types of photoreceptor cells in our eyes, mantis shrimp have between 12 and 16 types of photoreceptors.

They see ultraviolet light and polarized light, and their eyes are so advanced that their retina processes visual information before it even gets to their brain.

Scientists are beginning to explore whether mantis shrimp eyes could even see cancer before it starts to spread.

What is it about these little creatures that makes them so fast, so ferocious, and so extreme?

And how do these obscure crustaceans harness the laws of physics in ways we have never been able to replicate?

Mantis shrimp are small, colorful, and aggressive crustaceans that live in tropical and subtropical waters.

But for all that, they're usually only about 10 centimeters or 4 inches long.

The very largest might get to be 40 centimeters or 15 inches, only a little bigger than a foot-long sub.

The order stomatopoda, to which all mantis shrimp belong, separated from other crustaceans around 400 million years ago.

Then, over the next 200 million years, the shrimp-like ancestor of modern mantis shrimps had some of their mouth parts morph into raptorial claws, giving them the predatory appearance of praying mantises, from which they took their name.

These types of mantis shrimp came to be classified as spearers, and their deadly claws shape everything from the way they hunt to how they live.

Take the world's largest mantis shrimp, for example, the zebra mantis shrimp.

It can grow up to 40 centimeters in size and hunts as an ambush predator, living in sandy burrows on the shallow seafloor, only its eyes poking out as it waits for its prey.

It's impossible for fish to hidden in the sand, and by the time it strikes, it's too late for escape.

The spears shoot out at a speed of 2.3 meters per second, impaling the fish on 10 sharp spines that jut out from its claws.

In one experiment, researchers found that most zebra mantis shrimp strikes were successful in capturing fish.

But if you've ever tried to trap a fly with your hand, you might be able to imagine how hard it is to snap up prey and hold onto it.

How do they do it?

First, there's the reptorial claw itself.

It's designed to be strong, but also flexible, because it needs to slice through soft flesh and then hold onto it while the fish tries to get away.

To achieve all this, the spear has several spikes, which are slightly hooked hollow beams made of several layers.

On the outside is thin, hard, and mineralized epicuticle decorated by serrations and grooves to lock onto its prey.

On the inside is a less mineralized region with fibrous layers of chitin protein to allow for flexibility.

Unlike something like a bee stinger or a mosquito proboscis, both of which are straight to maximize how deep they can penetrate, the mantis shrimp's spearing claw is curved.

This helps it hold onto its prey.

To understand more about the ecology of mantis shrimp, we talked to Dr. Maya DeVries, who spent years studying mantis shrimp both in the lab and in the field.

When we capture them in the field, we do take advantage of their prey mechanism.

We'll put squid or fish on a lure, and then we will lure them out of their burrows that way.

And then we have like a little noose that's around the burrow, so it comes out and then we're able to kind of hook it.

The next element of the spearer's strike is how it achieves such high speeds.

First, flexor and extensor muscles in the marus are engaged.

The extensor muscles compress the claw, while the flexor muscles trigger a latch to lock into place.

When the flexor muscle relaxes and the latch slips open, the claw strikes out at incredibly high speeds, while at the same time the mantis shrimp lunges out of its burrow.

With a fish now trapped in its claws, it drags its meal back into the sand to feast.

And we couldn't resist asking Dr. DeVries the burning question on our minds.

Um, have you ever been speared?

Thankfully, never a spearer, never conspired.

That sounds scary.

Because these mantis shrimp live in the sand, it's pretty easy to move from one place to another.

That means they tend not to be very aggressive when it comes to defending their homes.

It just isn't worth the risk of injury.

But that is absolutely not the case when it comes to the other type of mantis shrimp, the ones with incredible smashing claws.

Somewhere along the way of their evolutionary path, a small subset of mantis shrimp changed from being spearers to smashers.

Instead of growing terrifying spines from their raptorial claws, these shrimp developed clubs that look much less formidable.

But looks can be deceiving, because these clubs achieve some of the fastest speeds in nature.

Whereas the zebra mantis shrimp can extend its spear at a speed of 2.3 meters per second, smashers like the purple spot mantis shrimp extend their clubs at a speed of 31 meters per second, with an acceleration of well over 100,000 meters per second squared.

This is an acceleration greater than a 22 caliber bullet fired from a pistol.

Their clubs can produce around 1500 newtons or 340 pounds of force, impact forces thousands of times greater than their body weight.

But when scientists were first studying the impact forces of these punches, something absolutely weird was showing up in the force graph.

There was one spike showing for the punch as you'd expect, but another second spike would happen soon after the punch.

And when reviewing the footage of this moment, the scientists saw something else weird, a bubble forming and a flash of light.

They realized that the mantis shrimp club was bouncing back after hitting the shell so fast that it creates a small area of extremely low pressure, and when pressure drops this low in water, the water instantly vaporizes, aka it boils.

This creates a vapor bubble called a cavitation bubble, but this bubble doesn't last long.

The pressure from the water all around the bubble forces it to collapse, and when this happens, energy is released in the form of sound, heat, and light.

This energy is so the surface of the sun, stuns the mantis shrimp's prey for a second time, and creates that second peak on the graph.

To understand this strange phenomenon, we talked to the scientist who first discovered it, Dr. Sheila Paddock.

So when we saw the cavitation bubbles for the first time, it really was like actually thrilling, and we knew that that that was probably the first time anybody had seen it because the technology just hadn't even been there.

We were using the newest, latest, greatest cameras.

Do you think part of why they evolved to move so quickly is to produce that cavitation bubble, or do you think the cavitation bubble is like a nice side effect for them?

You know, my careful scientist answer would be, I don't know.

Just as a, as an observer, I would say that they did evolve to cavitate because it's so robust, like it's just no matter what they hit, it cavitates.

They don't cavitate at the wrong time, they cavitate at the right time.

Some of the data we have show that you'll have like four peaks in a row that are evenly spaced.

So to me, that looks to me like something that has actually evolved, whereas some of the other animals that we've studied that cavitate, including this really hilarious tiny shrimp that we published about, also has an incredibly fast-moving appendage that shoots a water jet, but it only cavitates if the look a bit more like an accident, um, as opposed to this sort of incredibly robust phenomenon with the, with the mantis shrimp.

Given how different the attack is for smasher shrimp than their spearer relatives, their prey is also very different.

They tend to eat things with hardened exoskeletons like oysters and snails.

With these prey, extreme force is necessary for cracking them A hint as to why this paradox might exist can be seen while watching a clubbing mantis shrimp prepare to break a shell.

First, it touches, wiggles, and positions the shell exactly where it wants it.

It taps the shell with its antenna, seems to wait a moment, and then it strikes.

The key to it all is in the moment it seems to be waiting.

This is the moment that enables the smashing mantis shrimp to be so fast, the moment this mantis shrimp needs to take to be able to strike, and the reason it prefers prey that won't really move while it prepares to do so.

The shrimp is winding up, spring-loading its claw to an extraordinary degree.

The spring in question is shaped like a saddle, which is made up of chitin and sits on top of the claw.

In the moment just before the strike, the shrimp's muscles compress it and holds it back with a latching mechanism.

Then, when it's time to strike, this potential energy is released and the club swings forwards.

This saddle-spring mechanism allows the club to be released at an enormous velocity, a much higher velocity than any muscle would be capable of producing by itself.

The spearing mantis shrimp also has a saddle like this, but it's much less effective.

The easiest way to understand it is by comparing your performance throwing an arrow versus launching one with a bow.

Just throwing the arrow using your arm muscles will probably not make it go very far nor very fast, but use those same arm muscles to flex a bow and then release the arrow with your fingers.

Suddenly the arrow goes much farther and much faster, and yet the energy input is the same whether or not a bow is used.

The only difference is the time over which the energy is released.

So in other words, it's a small amount of energy, but the intensity of the release is extremely high.

So a lot of people are like, oh you know they're very powerful animals and they use so much energy, but actually they just really don't.

They use very little energy and they release it over short periods of time, which is very explosive.

The design of their raptorial claw is also quite different than the spear shrimp.

Because the club has to withstand such immense forces repeatedly, the exterior of the club is covered by a crack-resistant coating, a little like the tape boxers use for binding their hands.

Underneath that coating are two regions with fibers aligned in different directions.

One area of fibers dissipates cracks, while the other stops the club from expanding on impact.

All of this means that the shrimp can batter away on a clamshell or even a glass aquarium wall without damaging its claw.

And we know that the mantis shrimp have a very good sense of the three-dimensional structure and mechanics of the shells that they're hitting, and that in fact they will hit the shells at the most efficient structural locations to break them.

So you give them a high-spired shell or globular shell and they'll hit them differently.

And we've seen from our physical models of mantis shrimp that that sequence that they're using is actually the most efficient to break those geometries.

Because smasher mantis shrimp hunt prey that live on rocks and coral, they also live in very different habitats.

And it turns out their clubs come in handy for more than just hunting.

By having that superpower appendage to break open snail shells, that means that that food is available to them, but it also means that they can use it for a bunch of other things like knocking out a crab.

Oh, and I should say, some species of smashing mantis shrimp build burrows with their hammers that they create by inside the coral.

They'll bang out all the little sections and they'll be like a perfect little house inside the coral, which of course is a very nice protected home.

They prefer hard substrates for their burrows, which means real estate is at much more of a premium.

The burrow needs to be big enough for them to fit, but small enough that they can block the get into fights over burrows.

And these fights can get very aggressive.

One group of researchers found that sparring strikes actually pack more energy into them than strikes used for predation.

So we had to ask Dr. Paddock the same question.

Is there ever any occupational hazard handling these guys?

Are your fingers ever in danger?

Yeah, no, I mean you do have to be careful.

The bigger problem is that they have a spike at the end of their appendage and if that goes in your skin, it's really unpleasant.

But, you know, I mean if you have a cat, you know, with claws, you know, you just got to learn how to work with the cat, right?

It's the same idea.

So it's pretty rare that anybody has a problem.

There are like kind of crazy stories out there about people who like lost a finger because of a mantis shrimp, but usually it's because, you know, they were like diving and they stuck their hand down the hole and then the thing hit them and then they didn't move and so then the animal speared them and then they get all the bacteria in their finger.

Like these are like, this honestly never happened to us and it never will.

Like these are just really weird stories that end up on the internet.

But for the most part, they don't even want to spear you.

Even the spearers don't want to spear you because if they get their appendage stuck in your skin, they're going to lose the appendage.

So more typically, they just hit you with the claw.

I've been hit a gazillion times, including in the field.

Because at the end of the day, it's dangerous to be a mantis shrimp.

Luckily, mantis shrimp have an incredibly hard armor over their body and especially their telson or tail.

And this armor has raised protuberances that protect them from fracturing, even when they take such heavy blows.

So it's clear that the different types of raptorial claws play a huge role in determining everything about the mantis shrimp's lives.

But it's not only their claws that dictate much of their behavior.

It's also their eyes.

Mantis shrimp are often said to have the most complex eyes of any creature in the animal kingdom.

And they might be the part of their body that makes them look the most alien.

And these eyes help them to be such effective predators.