This episode of Because Science
is sponsored by Shadow of the Tomb Raider.
Here's everything you need to know about the Predator.
Keep moving boys, he's around here somewhere.
(shushes)
We're trying to get the jump on
the deadliest humanoid this side of Andromeda.
It's already wiped out half my Kyle.
So just in case something happens to us,
I'm gonna tell you everything that you need to know
about the invisible, heat-sensing,
glowing-blood monster that is the Predator.
First appearing in 1987's classic, Predator,
the extraterrestrial hunters later known as
the Yautja, are arguably some of the most
iconic monster designs in all of cinema.
The aliens are extremely proficient killers
who sport a combination of interesting biology
and cutting-edge technology,
while tracking down their exo-trophies.
They may be inherently mysterious creatures
but we can use science to de-cloak the Predator's
most famous properties, before it's too late.
Let's start with maybe the most visible thing
about the Predator, its glowing blood.
Since this blood glows all by itself
night and day, right out of the body of the creature
like a glow stick, it's probably bioluminescent.
Or more generally speaking, chemiluminescent,
meaning that the light produced by the blood
is due to a chemical reaction.
The same kind of chemical reaction
that wonderfully illuminates firefly butts.
In chemiluminescent reactions, atoms are excited.
They get energy in just the right way.
When they finally relax, or return to their ground state,
they release some of that energy
in the form of photons of ligh...
Oh keep moving!
To be bioluminescent you need
two essential pieces of chemistry.
One, a molecule that can emit light,
and two, a molecule that allows that reaction to take place.
Now, because bioluminescence, as far as we know,
has evolved on Earth 40 separate times,
we use general terms for these two pieces of chemistry.
A luciferin emits light, and a luciferase allows
the reaction to take place, it's more of a catalyst.
Lucifer because in Latin it means light-bringer.
It's not like we're not gonna be
summoning the Devil with chemistry.
(ominous chanting)
No.
Let's say we have a molecule like firefly luciferin
and it's in the presence of its luciferase,
which I'm choosing to depict
as Arnold Schwarzenegger's bicep.
Now when the luciferase is in the presence
of its luciferin, it allows the luciferin
to react with something energetic like oxygen,
which I am choosing to depict as Carl Weather's bicep.
Now this excites the Luciferin
and so when it returns to it's ground state,
when it relaxes, it releases some extra energy
in the form of a photon of light.
Now, enough of these microscopic reactions happening
produces a macroscopic glow.
Predator blood then, most likely contains
a luciferin and luciferase that when exposed
to Earth's atmosphere causes the blood to glow.
Now this would make it unlike any animal blood
we know of here on Earth, but there are materials
on this planet that glow in the presence of oxygen.
In fact it was alchemist Hennig Brand's
discovery of elemental phosphorus
that coined the term phosphorescence.
Its oxidized vapor glows a faint green
just like the Predator's blood.
And Brand wasn't even trying to find phosphorus.
He was boiling pee with the hopes
of turning worthless metals into--
Oh boy.
Don't sell my hair on eBay!
Wow, I bet that guy wishes he could turn invisible.
Too bad that's something the Predator already figured out.
Better keep moving.
Predator camouflage is almost as famous
as the creatures themselves.
Predator camouflage does not give
the creatures true invisibility, where photons
of visible light will be passing
right through them as though they weren't there.
No, their version is a more adaptive camouflage
that reacts to their surroundings
but can still give away their shape.
This is more of an active camouflage,
which would certainly have to be high-tech,
but that does not mean that nature didn't figure out
something very similar millions of years ago.
(grunts and splashes into water)
The best camouflage in the animal kingdom
has to go to the octopus and the cuttlefish.
These creatures can change their shape,
their skin color, and even their skin's texture
in response to their environments.
The cuttlefish has such amazing control
over its active camouflage, that it can use it
to actively disorient their prey.
But the creature with maybe the closest thing
to what the Predator is doing is the firefly squid.
Now, imagine that we are Predators looking up towards
the ocean's surface for tasty, tasty squid to eat.
Now, with the sun coming down in one direction
towards us towards the sea floor,
the squid's outline is very easy to see.
And under this selective pressure,
the squid has evolved bioluminescent counterillumination,
which makes the squid brighter, relatively speaking,
to its background and thus makes it harder
for us as Predators looking up to see.
Now, the Predator uses this same idea,
using light to better match it's surroundings.
It just takes it to a whole 'nother level.
How am I breathing?
Doesn't matter, no time, gotta swim, gotta go.
This Predator technology appears
to be all about using light to match surroundings,
like squid counterillumination, and if that's the case
the Yautja are probably doing something similar
to what our researchers are already looking into.
Japanese researcher Susumu Tachi
came up with this Predator-like camouflage
by first imaging the objects behind him.
And then he projected those same images
onto the surface of his body, but he was wearing
highly reflective clothing, and it looks pretty good.
Of course Predator technology
would be way, way more advanced.
They'd have to image and project
simultaneously on their bodies,
kind of like this now famous Halloween costume.
So maybe they could for example miniaturize
thousands and thousands and thousands of screens,
like these iPads, and then put them around their bodies
so that it could hide what they wanted to
while still giving away their shape.
That might work.
And now that you have this information
there's no more narrative reason for me to be here,
so I will just stand here nice and safe
with my spine remaining in my body.
(Predator snarls)
Oh boy.
Delete my browser history--
Wow, that sounded violent.
There's one more thing that
you should know about the Predator.
It has eyes unlike anything in our animal kingdom.
Predators are deadly trackers and one of
the big reasons why is that they can see heat.
Everything with a temperature emits
so-called black-body radiation
across the electromagnetic spectrum.
But depending on the temperature of that something,
that radiation will peak at certain wavelengths.
For example, ultra-hot objects like stars
can emit most of their black-body radiation
in the x-ray and ultraviolet wavelengths.
Whereas comparatively cooler objects like campfires
will emit most of their black-body radiation
in the visible to infrared range.
Using what's called Wien's displacement law
in human body temperature, we can calculate
the peak wavelength for human heat
and you get about 10 micrometers, infrared light.
This must be where Predator eyes are sensitive to
if they are hunting us so effectively.
And if that's the case, if they are sensitive
to this range of light, it makes their eyes really special.
What? Squid? Here? Why? How?
Doesn't matter, no time, gotta go.
There are some birds that can see in ultraviolet.
There are some snakes that have heat-sensitive tissues
integrated into the visual parts of their brain.
But as far as we know there are no organisms on Earth
that can see infrared light like the Predator can.
Evolution on Earth has apparently kept vision
in a tight radiation range because physics.
If the cells in your eyes were sensitive enough
to pick up minute traces of infrared light
like the Predator can, you would be able to
see the heat of everything and therefore nothing at all.
If you could see beyond ultraviolet light energies,
light would be energetic enough
to start damaging your squishy equipment.
And so the cone cells in your eyes
that allow for color vision are most sensitive here
to blue, green, and red wavelengths of light.
The Predator's eyes would have to be sensitive
to wavelengths off of this screen over there somewhere--
Oh crap.
Wait, but wouldn't the mud just heat up and then he'd be--
(cries in surprise)
Okay I think we're good.
At the backs of your eyes you have rod and cones cells
that are sensitive to photons of certain wavelengths.
When an incoming photon strikes the back of your eye,
it changes the shape of specific proteins
which causes a cascading signal of electricity and chemistry
that eventually ends up in your brain as vision.
To see in infrared in a way that evolution
here on Earth has disfavored, Predator eyes
would have to be very different from our own.
They would need cells and proteins
that are currently unknown to science.
They would have to be able to create signals
from these cells and proteins that are so specific
and so perfectly processed in their brains, that their eyes
and brains are not overwhelmed by ambient heat
and their eyes would have to be structured differently
to accommodate the longer wavelengths of infrared radiation.
Oh.
(Predator clicks)
One of Kyle's hair ties.
(Predator clicks)
Okay, thanks.
So that's everything you need to know about the Predator.
Its blood is bioluminescent in our atmosphere.
Its camouflage is like a high-tech
cuttlefish mated with an iPad.
And inside its eyes is delicate alien biology
so sensitive that it can see a wavelength
of light that is invisible to us.
Good luck, you're gonna need it
if you want to get to that chopper.
(Predators all click)
(sighs)
Because Science! Oh! Ouch!
(techno music)
Now, I haven't been to a jungle to use infrared vision,
but I would imagine that infrared vision
would be terrible to use in a jungle
just because of the higher background ambient heat.
What some snakes do that sense heat
is they will cool themselves down in the desert sand
and wait until nightfall so that when the animals
they want to hunt come out, they are much hotter
than the background cooled sand
of the desert, and the snake is also cool
so that infrared signature pops against that background.
But if the background is 90 degrees fahrenheit
because it's the jungle, the background radiation
is gonna kind of match the body heat of,
lets say, a human, and it would be very hard
to discern that human signature from the jungle signature.
But I'm sure, I'm sure they thought of that.
Thanks again to Shadow of the Tomb Raider
for sponsoring this episode of Because Science.
Become the Tomb Raider you were meant
to be in Shadow of the Tomb Raider.
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from the impending Maya apocalypse,
and uncover your destiny as the Tomb Raider.
Survive the deadliest place on Earth
by becoming one with the jungle environment,
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Explore and discover this wild environment
with all of its mysteries ready to be revealed.
Shadow of the Tomb Raider releases
on all platforms September 14th.
Pre-order the Croft edition to play right now.
Become the Tomb Raider.
Hey, I'm still alive.
Thank you so much for watching Christina.
If you want more of me you can
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(laughs)
(synthesized tune)