How Different Animals See The World


– [Steven] Humans have a lot
of advantages over animals. We have languages, opposable thumbs, and most of us are a lot
smarter than animals. Our eyeballs, as it turns
out, are pretty boring. Many animals have eyes
that let them see the world much differently than we do, so let’s find out how exactly how the animals of earth view the world! – Amazing. – [Steven] Number 20, dogs. We humans have three different kinds of color detecting cells in our eyes, they’re known as cones,
whereas dogs only have two. The cone cells that dogs have are only capable of detecting yellow and blue-to-ultraviolet light. Each type of cone contains a pigment that is sensitive to a
different wavelength of light, so the range of color
that an animal can see depends on what combination
of pigments they have. Since dogs have fewer cone types, they are not able to see
as many colors as we can. Many people believe that
dogs see in black and white, but that isn’t true. A dog would see a rainbow
as light blue, dark yellow, light yellow, white, and very dark blue. Pretty drab. Number 19, geckos. Human cone cells need pretty bright light in order to function well, which is why we cannot see
colors that well when it’s dark. Luckily we also have rod cells which help us see in low light, which has a single
light sensitive pigment. Unlike humans, geckos
have great color vision even in the dark. Dark doesn’t even look that dark to them, since their eyes are 350
times more sensitive to color in low light than ours. Geckos evolved to have these eyes because they hunt at night. Number 18, giant clams. As it turns out, giant
clams not only have eyes, but have a few hundred eyes
about the size of pinholes all along the edge of their bodies. Their eyes are shaped like a cup and have very narrow
openings, and unlike our eyes, they do not have a lens. Giant Clams are sensitive to three different colors of light, but they cannot combine that information. This means that they see
colorful, but undefined images. They can detect movement, however, which is all they really need to get by. If they see a nearby predator, they can squirt a jet of water at them or close their shell in self defense. Number 17, jumping spiders. Jumping Spiders are like
regular spiders except worse because they can quickly
jump away from the newspaper you’re trying to smash it with and they have great vision. Like most spiders, they have eight eyes with which to detect potential prey. Their biggest pair of eyes faces forward and gives them high resolution
vision for seeing detail, and their other smaller eyes
toward the back of their head to give them peripheral
vision and motion detection. Jumping Spiders can also
see more colors than we can due to their special pigments which are sensitive to ultraviolet light. Number 16, Mantis Shrimp. You’ve probably heard of the Mantis shrimp because of their famous
aquarium glass shattering punching capability. Well, as if they even needed other superhero-esque abilities, it turns out they also have
freakishly good eyesight. In fact, they have one of
the most elaborate eyes of any animal on earth. As mentioned before, humans have three types
of cones in their eyes. Mantis shrimp have 16. Mantis shrimp can also
tune the sensitivity level of their vision at will to
adapt to different environments. Scientists have yet to
discover another animal that can do that. Who would have thought that the
most intricate visual system on earth would be attached
to this weird shrimp? Number 15, bees. If you’ve seen the Bee Movie, you already know that bees are important. But what you may not know is that bees have 1,000
eyes as opposed to two. Bees, like many other
insects, have compound eyes that are made of many ommatidia, meaning each act like an individual eye. They all point in slightly
different directions, which gives bees a wider
angle of sight than humans. The image that bees see
is not as sharp as ours, but it does let them see up
to 300 pictures per second, versus humans, who can only see 65. Number 14, cats. If you’ve ever wondered
why sometimes cats’ eyes will be a different color in a photo than they are when you look at ’em, this is due to the tapetum lucidum, a reflective layer behind the retina that redirects light back through the eye. This works in the same way that
shining a light at a mirror creates more light than
shining one against a wall. The tapetum lucidum means that not only do cats
see better in the dark, but they actually see better in the dark than they do in the light. Number 13, flies. Flies can see limited colors, but they have a very
broad field of vision, and see in a sort of mosaic effect. The reason flies can
seemingly almost always escape from whatever you’re
trying to kill them with isn’t because they’re psychic, but because they literally
see the world in slow motion. They’re like Keanu Reeves in The Matrix, except all the time. This was discovered in a study that tested different animals ability to detect separate flashes
of fast-flickering light. Scientists found that time perception is directly related to size and how fast an animal’s
metabolic rate is. So the tiny fly, with it’s
extremely fast metabolic rate, can easily react to and escape
your fly swatting attempts. Number 12, snakes. Some animals, like snakes,
don’t see color at all. Snakes that spend most
of their time underground have small, simple eyes
that only differentiate between light and dark. Snakes that live above ground and need their vision for hunting prey have very clear vision as
well as good depth perception. Certain species of snakes,
such as boas and pythons, also have what are called
‘pit organs’ on their heads which can see heat sources. So, they essentially have their own pair of built in infrared goggles. Number 11, cows. Cows seem like pretty boring animals, so you’d expect them to pretty
much see the way that we do. You would be wrong. This is what cows have
tricked you into thinking. Most cows do see limited colors, since they’re red-green color blind. They see mostly gray and black, but also versions of yellow
and blue, since unlike humans, they only have two color receptions. Cows also have what is
known as ‘panoramic vision,’ meaning that they can
see in all directions without having to move their heads. Cows can see 300 degrees just
by moving their eyeballs, which only leaves a small blind spot on the back of their heads. Good luck trying to sneak
up on one of these guys. Number 10, birds. Vision is particularly
important for birds, since you don’t want to hit something while you’re 50 feet in the air. They have the largest eyes
relative to their size in the whole animal kingdom. Unlike humans, who have
three color receptor cones, allowing us to see red, blue and green, birds have four cones, so they can also see in
the ultraviolet spectrum. That’s pretty handy because the high
phosphorous content in urine glows brightly, allowing
birds like kestrels to track prey like voles
by their urine trails. Impressively, birds
can also rapidly change the shape of their eye lens, similar to how a camera functions, and they have a third, transparent eyelid. So, some birds of prey can
basically see much like a camera with both a macro lens and a zoom lens, to focus on multiple things at once. Particular kind of birds even have their own special eye abilities. For instance, nocturnal birds such as owls actually have tubular eyes
rather than spherical ones, allowing more light to enter the eye for a brighter more crisp image. This makes it especially
handy for night time hunting. Some sea going birds even have
red or yellow oil droplets inside their eyes, which allows them to
see in hazy conditions. Number nine, horses. Horses have some of the largest
eyes of any land mammal. Because their eyes are on
the sides of their heads, they have an even greater
field of vision than cows, capable of seeing 350 degrees
without moving their head. Horses see the world in only
two colors: blue and green. This is why in show jumping, where in people train horses
to jump over obstacles, the obstacles are always brightly colored, contrasting heavily with the ground. A horse would have a hard time
distinguishing an obstacle that was only a few shades
different from the ground. Number eight, frogs. Frogs are near-sighted, therefore they can’t see
at distances that well. Their eyes are extremely
sensitive to movement, so if a frog’s prey does not
move, they will not detect it. They also have excellent night vision due to a mirror like layer
in the back of their eye called tapetum. While the extent to which
frogs can see colors has not been determined, they do have some ability
to detect different hues in the environment around them. In fact, frogs may even
be able to detect color in extremely low light situations where other animals
only see shades of gray. Frog eyes are especially
interesting to humans, since they can actually
regenerate certain structures if they’ve been damaged. Scientists believe that
by studying frog’s eyes, they could discover a cure
for certain vision problems in humans. Frogs also use their eyes
to help them swallow food. After a frog has its prey in its mouth, you will then see it retract
its eyeballs into its head, actually pushing the food down
and lettin’ the frog swallow. Hopefully, scientists do
not research this aspect of frog vision any further,
because that’s really gross. Number seven, chameleons. Like birds, chameleons can
see all the colors we do, plus ultraviolet light,
which we cannot see. The most interesting thing
about their sight though, is that a chameleon’s eyes
move totally independently from one another. This means that a
chameleon can keep an eye on two things at once, even if those things are
in opposite directions. Not only can they look in different directions at the same time, but they can focus their
eyes at different levels at the same time, enabling them to view nearby
objects and distant ones at the same level of focus simultaneously. Number six, starfish. For a long time, scientists wondered if
starfish could even see at all. It was known that they have
one eye on the end of each arm, but it wasn’t clear if they
could actually see images out of them or not. Recently, however,
scientists have discovered that starfish can indeed
see very basic images- about 200 pixels. I guess some vision is
better than no vision. What would a starfish need
super jacked up eyes for anyway? Number five, cuttlefish. The adorably named cuttlefish has blurrier vision than we do, and are completely colorblind. Cuttlefish have one photoreceptor that shows them shades of gray, and another that detects polarization. The only time a human will
experience polarized light is when they wear
sunglasses that reduce glare by filtering out an
orientation of light waves. With the help of modified
LCD computer monitors, researchers were able
to give us an impression of the changes in polarization
that cuttlefish can see by changing the colors on
screen, like in this image. Of course this is just a
representation for us to understand just how sensitive cuttlefish eyesight is, since cuttlefish are actually colorblind. So, what’s the point of
cuttlefish being able to see this? Well, cuttlefish can also
produce polarization patterns on their skin, which scientists think they
may use to communicate, kind of like signal flags. Number four, butterflies. Butterflies see with red, green, blue, UV, and the wideband light from red to purple. This really isn’t much, but, like bees, it does enable them to detect pollen, and at the end of the day
that’s really all they need. Though they have only 0.04
the visual acuity that we do, meaning that they can barely see something that’s 50 centimeters away from them, they can still track
down pollen on flowers. Number three, garden snails. A snail’s eyes are located at the the tip of their two smallest tentacles. Because snails can move these tentacles around as they please, snails have a very wide frame of vision. If only our eyes were not
stuck in our lame skulls, we could do the same thing. Garden snails cannot focus or see color, but they can detect
movement and differentiate between different intensities of light. This allows snails to move towards the sorts of dark places that they like. Number two, rabbits. If you’ve ever set a treat
down right in front of a rabbit only to have it seemingly
ignore it, don’t worry, it’s not trying to tell you
that your offering is unwanted, it probably just can’t see it. A rabbit’s eyes are so far down its head that it actually has a blind spot right in front of its nose. Try moving your treat slightly
to the right or the left. This unique eye positioning also means that rabbits have very
poor depth perception, since their eyes have little overlap. Rabbits see objects on their
right with their right eye, and vice versa. Number one, turtles. While it is commonly believed
that turtles are colorblind, in reality, they are better
at seeing color than we are. In fact, compared to turtles,
we’re the colorblind ones. Turtles can see one extra
color which humans cannot. The color is referred to as ‘red,’ though it is ultimately
impossible to a human to picture just what
exactly this bonus color is. Now that you know all these
secrets of the animal kingdom, are you still content
with your human eyes? Do you feel slightly
visually inferior like I do? And, which animal’s vision would you most like to
see the world through? Let me know what you think in the comments section down below. Thanks for watching! (light music)

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