Claire Corlett

Fish Food, Fish Tanks, and More

The Snail-Smashing, Fish-Spearing, Eye-Popping Mantis Shrimp | Deep Look

The mantis shrimp is a true heavy-hitter. Take this one. She’s about to devour this snail. But she’s gotta crack it open first. So, she carefully positions it… Then — BAM! — she punches it with the speed
of a .22 caliber bullet. It’s the fastest attack in the animal kingdom. That’s one kind of mantis shrimp, known
as a smasher. Here’s the other. This one’s called a spearer. Buried up to his eyeballs, he watches and
waits. Then springs into action, impaling his prey
on serrated blade with blinding speed, and dragging it beneath the sand. What makes these two so amazing isn’t just
their speed. It’s their eyes. See those black spots? They’re like our pupils, where the light
enters the eye. We humans have one in each eye. Each sends an image to the brain… and voila…
depth perception. The mantis shrimp has six of them. Our vision: binocular. His vision: hex-nocular. For when accuracy counts. As for color? We’ve got 3 receptors, red, green, and blue. The shrimp has 12. Another world record. But there’s even more to this incredible
eye. And it has to do with something called polarized
light. Sunlight is messy. It’s a jumble of wavelengths, moving in
all directions at once. But some surfaces — say the scale of a fish,
or a pair of polarized sunglasses — have a way of changing the light, organizing it,
so it moves in a single plane. We humans can’t really tell this is happening. But the mantis shrimp can make out where in
the ocean light is being polarized and where it isn’t. Some mantis shrimp take this one step further,
and produce their own special kind polarization. And they use it as a kind of secret code. See, mantis shrimp are incredibly territorial. They will defend a burrow to the death. But some, like our smasher, have a way of
avoiding the fight. When he looks into a burrow, he can tell that
another mantis shrimp has already claimed it, by the way light is hitting its body. That’s the secret code. Here’s how it works. Remember when I said that polarized surfaces
organize light into a plane? Well these surfaces on the mantis shrimp make
the beams of light circular, spinning through space like a helix. And as far as we know, only other mantis shrimp
can can detect this with their eyes. You can see it here because we put a polarizer
on the camera. So, these shrimp have taught us a thing or
two. By reverse engineering the mantis shrimp’s
eye into a camera, a group of scientists have begun to use polarized light to diagnose injuries
and disease. This scanner measures polarization in red. See how this mouse tissue goes red when it
stretches? Well, injuries to our tendons do the same under the scanner. So do some cancers. This endoscopy footage reveals cancerous cells
hiding in plain sight by the way they react to polarized light. It just goes to show how we see the world
differently when we look at it through another set of eyes. Hi, It’s Amy. I wish I could say that no snails were harmed
in the making of this video. But a shrimp’s gotta eat. And so do we! So subscribe. See you next time.

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