Why Do Some Animals' Eyes Shine In The Dark?
Ғылым және технология
When an animal's eyes shine in the dark, it's because of a structure inside the eye that helps them see better in dim conditions. Learn what that structure is and how it works.
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Research Sources:
● www.npr.org/templates/story/st...
● animals.howstuffworks.com/fish...
● Ollivier, F. J., Samuelson, D. A., Brooks, D. E., Lewis, P. A., Kallberg, M. E., & Komáromy, A. M. (2004). REVIEW Comparative morphology of the tapetum lucidum (among selected species). Veterinary Ophthalmology, 7(1), 11. doi:10.1111/j.1463-5224.2004.00318.x
Script:
There’s something really spooky about the way some animal’s eyes shine in the dark. My grandmother… she called it The Shining! But most people refer to it as Tapetum Lucidum, a reflective surface behind an animal’s retinas. It’s a common feature in vertebrates that do stuff in low-light environments. It enhances their visual sensitivity so they can see better in near darkness.
When light enters an eye, lots of it hits photoreceptors that then transmit visual information to the brain. But some photons slip past the receptors, so the tapetum lucidum acts like a mirror, bouncing the light back for a second chance at being caught.
The tapetum lucidum is usually located behind the retina and is made up of mirrored crystals that reflect light. Lots of different animals have these, so there’s a broad diversity of how they’re structured. Depending on the animal, there may be several layers of both high- and low-refractive index materials in the tapetum. These layers are compatible with different wavelengths of light. And depending on the structure of these layers and the particular light wavelengths in play, they’ll either enhance or interfere with night vision.*
And the more layers there are, the more effective it is at reflection. A tapetum with five layers would only reflect up to 75% of the light that hits it. Between 10 and 20 layers means that an eye could approach a reflection rate of 100%. Keep in mind, however, that blood vessels, cells and imperfections in the tapetum layers can all interfere with the reflectance.
But what about all the animal variations out there? Well, among mammals there are more variations within the carnivore family, probably because most of these animals are active at night. Herbivores are more diurnal, meaning they sleep at night and party in the day. As such, they have less evolved tapetum than their nocturnal, blood-thirsty cousins.
There are three basic tapetal morphotypes in vertebrates, classified based on where they’re located and the composition of their reflective layers. First there are animals without tapeta lucida. This includes humans, other primates, squirrels, pigs and birds. In fact, birds are the only large group of animals where the tapetum is consistently absent. If you see any reflection in these animals’ eyes - like when you have redeye in a photo - that’s light reflecting off blood vessels at the back of the eye.
The second type are animals with tapetal material located within the retina itself, making it closer to their eye’s photoreceptor cells. This is most common in fish and some reptiles and only occurs rarely in mammals like fruit bats and opossum.
The last type are animals where the tapetal material is inside the choroid, vascular layer of the eye that’s over the retina. Lemurs have this, as do cows, sheep, horses and the aforementioned harmless kittens. You know what else has eyes like this? Sharks! And the tapetum lucidum in a shark makes it so they see 10 times better than humans can in dim light.
Here’s another difference: Not all tapetum lucidum shine with the same color. Whether they’re yellow, green, blue or whatever, the hue comes from different substances within the layers, like riboflavin or zinc in the tapetum or varying pigments in the retina. And these colors aren’t necessarily the same within each species or even each breed. For instance, age can change the color - so two Chihuahuas’ eyes might shine differently.
Пікірлер: 120
aww, I wanted to see what Josh was going to say after he said "yes", so happily at the start of the video.
@neeksbeek9920
2 жыл бұрын
jahahhahahahahahaha i laughed so hard
@jadibdraws
2 жыл бұрын
Right like what the heck did he say for them to cut it out.
@josecattani5331
Жыл бұрын
Comedy gold tho
I have two dogs . Ones eyes shine light blue . That's the non demonic one , the other is a toy poodle who's eyes shine red . It has Tapetum Lucifer eyes and is obviously possessed by the dark lord . It explains a lot about that dog .
@cheesyfries5638
Жыл бұрын
Dark Lord Poodle
Lmfaoooooo "Yes!" *looks to elaborate then edited*
@BookOfMorman
3 жыл бұрын
lolololol
0:32 i really wanna know what happened after that
Both of these people come off as being so incredibly uncomfortable being on camera...bad editing...made it hard to watch.
@jadibdraws
2 жыл бұрын
Right like wtf I'd the editor doing they have to be 60+ that's the only way this level of bad editing is acceptable or a child
0:36 ... awkwardddd
There are some animals with red eye shine, like the barred owl. The first time you see that magnificently creepy sight you’ll be properly spooked. Not sure why they’re different.
At 2:50, it is mentioned that bird retinas never have tapedum lucidem. This is not true; crows, owls, bat hawks, frogmouths, and night jars (among other nocturnal hunters and foragers) are known to have this retinal layer and excellent night vision.
@craigsaunders7037
2 жыл бұрын
Yes , I thought BS on that also .
Keep up the awesome work!
@Evan Lyle -- There's been a bit of debate over the past couple hundred years about whether some animals that display eyeshine have a true tapetum lucidem or whether they have a distinctly different but tapetum-like structure. From what we've read, the general consensus right now seems to be that birds do not have tapetum lucidem. Here's one of the studies we looked at: www.ncbi.nlm.nih.gov/pubmed/14738502. Thanks for asking! /Lauren
@appletree8441
4 жыл бұрын
Well birds just might have very good night vision with out it. But he Ven that some birds like owls hunt at night whilst other just hunker down. There must be something going on
@filiphabek271
3 жыл бұрын
Then what do birds have that reflects light?
I can always tell my one cat by his eyeshine because his eye is scarred and it makes one of his eyes look dimmer.
my dog's eyes shine in green! creepy as heck
@uhohstinky7284
4 жыл бұрын
The Josie Franco same
@cupidkira1738
4 жыл бұрын
Mines shine red
Josh, you're awesome.
It's like howstuffworks decided it wasn't simple enough and further reduced their target audience to 5 year olds.
0:36 lol?
@bloofle674
10 жыл бұрын
Yes! ...
@SonicBoone56
10 жыл бұрын
He probably didn't get what she said.
@djteranova5859
6 жыл бұрын
ILoadng Cringiest
I'm very curious and have never seen any information on this, do the different colors of the Tapetum allow animals to see different wavelengths? If so, what wavelength of light does each color enhance?
Sometimes I just watch a video cause of Lauren. Just liking the way she talks.
@ss4viper
10 жыл бұрын
Totally agree
Awesome. Thanks a lot
My miniature schnauzers all have blue eyes in photos.. cool info!
Why do my eyes shine bright blue light in the dark? Am i the only person in the world? All my friends think its special and they are jealous of it but some people told me its creepy, how is this possible? I never saw it on other people and when i search it on google i find no result.
@nashnash5515
3 жыл бұрын
That happens with me lol
Love that box gap lauren.
When I grow up I want to be Josh, he's the best part of this channel
I'm Josh too...awesome video great job 👍
wait, so I'm not suppose to have glowing eyes? should I get it checked out?
that red eye on cameras thing was really interesting I never knew that :)
Actually this whole episode was awkward :O
question.. Why do some animals such as dogs seem to have multiple/rainbow eye colors?
What about Owls? You say that the tapetum lucidum is "consistently" absent in birds, but owls are birds and they hunt primarily at night? They actually have a larger eye structure more of rods and a tapetum lucidum.
Can you help me my eyes glow red in dark too
I love her hair colour.
And to think human eyes just get a bit more sensetive and open their pupils wide when in the dark. I mean, my eyes seem to work a lot better than most people's in the dark, but I imagine they're also hurt by sunlight for the same reason.
@giga0298
Жыл бұрын
My eyes see great in the dark and glow
@suruxstrawde8322
Жыл бұрын
@@giga0298 Technically all humans have glowing eyes but they can’t see the UV pink it appears as without thesis of cameras. That’s what red eye is, bugs can see that tho.
wow this was awesome =D
So why don't photos of blood or blood vessels reflect as brightly as red eye photos do?
That's a mock mic on Josh. Hi Lauren 😍
Tapetum isn’t the first layer on pollen grain. Read in class 12🤔
Humans have not much of a tapetum lucidum at all, so they still have it, but it only partially works, a mutation can cause this structure to be bigger than normal.
My dogs eyes illuminate demon red. I can see my devil dog from across the back field at night.
@makaylacree2965
3 жыл бұрын
😭😭😭
When I say to my mom that I haven't done my Homework then her eyes shine red. What's that..?
We answer the age old question: "Why Do Some Animals' Eyes Shine In The Dark?"
@Holobrine
10 жыл бұрын
So I have 2 bi-eyed dogs. That means they each have a brown eye and a blue eye. As a result, it appears that they have different colors of eye shine.
@Some_Random_O_O
6 жыл бұрын
Can a human have this happen because i saw a human with glowing eyes and it was as fast as a car
I thought our photoreceptors are sensitive enough to register single photons. Just a matter of surface area between them?
I have know people that take pictures and they have red eyes but I have taken a picture and had yellow glowing eyes no blood vessel red eye so was that like 0.2 percent of tapetum lucidum
Bruh is this the editors first time editing? Lol
Thats their night vision so they can see in the dark like wolves see extremely well at night
So you are saying that a couple of small round mirrors in the darkness of night (that reflect>95% of light) will “glow” similar to a raccoon or bob cat? Humm, not buying that. Never noticed a car’s side view mirrors ever doing anything like that.
What you don't know is that Josh is the brains behind BrainStuff. You herd it hear furrest, bit chezz. glaven...
How about Riddick, His eyes glowing in the dark too.
@Jackkenway
8 жыл бұрын
+Iron Bryan Hats off!
@suruxstrawde8322
6 жыл бұрын
Same thing, this is immediately what I thought of the first time I saw his eyes.
HAVE
What about owls?
My dog eyes glow in the light when the sun it's shinning
when i have foor and my dog looks at me his eyes shine orange
What about pink eye?
I have 2 dogs, the older (a german shepherd), has tapetum lucidum that shine blue. the younger (a Siberian husky puppy) has eyes that shine red....explanation?
@julianlaresch6266
Жыл бұрын
The puppy is possessed by the devil
orange
! _! Really wanted to hear him elaborate before getting crudely cut off
She looks like "Mai" from ATLA.. :D
my dogs shine bright like a diamond!
So if I understand correctly not all of the animals see with same clarity in the dark, right? One more thing you said birds can't see in the dark... at all! How about owls we see 'em at night but they can't see a thing?!
@BrainStuffShow
8 жыл бұрын
+Jack Kenway Different animals do indeed see with different levels of clarity in the dark. But other structures in the eye also help with that. (Humans don't have a tapetum lucidum, and we can see a little bit in the dark!) Cells in the eye called rods are specialized to detect light in dim situations. Some birds have very few rods and are almost blind at night. Others, like owls, have LOTS of rods and can see just fine in the dark. Here's a pretty good explanation if you're still curious: www.birdwatchersgeneralstore.com/NightVision.htm /Lauren
@Jackkenway
8 жыл бұрын
+BrainStuff - HowStuffWorks Oh I see, yeah because it was a little bit unclear when it comes to birds now I got it! Thank you very much, I really appreciate it! And thanks for that article, I never knew that some birds can see color, and depending on their hunting patterns or whether they are nocturnal or not, they have more rods and less cones and vice versa... thanks again!
This is not Sense I can see on the dark when I turn on my flash light
There's this Chinese kid that has a tapetum lucidum.
@toleyk
10 жыл бұрын
Sorry that was a hoax.
@AntMixFilms
10 жыл бұрын
Really? That's a disappointment... :\
Lauren. ... so elegantly pretty. She does kind of a Emperor Palpatine thing with her hands but it's ok lol.
@BrainStuffShow
9 жыл бұрын
This is probably my most-favorite compliment ever -- Emperor Palpatine is pretty rad. /Lauren
But the moth man has red eyes..... owls too
This acting scares me
I didn't like the way of guys are explaining. It has to be direct and to the point.
Lol wat was josh gone say😂😂
#Vegan for Animals.... Plants don't feel pain but Animals do.
Ive definitely seen peoples eyes glow
@kronosx7
10 жыл бұрын
No you haven't.
@magvox2
10 жыл бұрын
You're right. I'm crazy
@magvox2
10 жыл бұрын
Thanks
don't owl eyes shine?
@ingramalastrine261
7 жыл бұрын
jonny pepperston They do. Most fishes, most mammals (except of primates, humans and pigs), like deer, bears, coyotes, wolves, marsupilas and some nocturnal birds (I guess it's in minority) all have it in it's eye
thanks for answer my other question 2 bonus question answer. 😂
Wow this was incredibly awkward to watch lol
You guys make me feel dumb lol
reminds me of the creepiest Chihuahua in the world; youtube "Rubber Johnny" by Aphex Twin.
Soo guy was cut off for MANSPLSNING
i wish my eyes glow
@appletree8441
4 жыл бұрын
Try nuclear materials. Go to a nuclear plant and ask for some
HH
Bad editing
weird acting x)
Or Jews when they see money.
cringe
Wake him up