Humans can see pretty well, not the best, but it works.
Until nightfall. Then our eyes are basically useless.
But turn the light out on a nocturnal predator, and they'll see just fine.
Okay so before we look at other animals' eyes, let's take a look at our own.
Okay so looking at the outside of your eye, you can see the iris, which is that colored part,
then we can see the pupil which is the bit that lets different amounts of light in depending on current light levels.
Going back a little bit we see the lens right behind the pupil and iris. This is what helps focus the light onto the back of the eye. Sometimes, the lens isn't properly shaped and can't focus light correctly, which is why some people have glasses.
Now, all the way at the back of the eye there are the cones and rods.
There are three types of cones in the human eye.
Each one is sensitive to different wavelengths of light (red, green, and blue), giving us color vision.
Now cones only work in high light levels, but then there are rods.
Rods can't see color but can see well in low light levels.
Okay so why can cats see in the dark but we can't? Well, that's because their eyes have something ours don't.
Cat eyes have a tapetum lucidum which is a reflective layer in the back of the eye that reflects light back into the eye, giving their retina a second chance to absorb it.
This is also why cats have glowing green eyes when you seem them in the dark.
While on the topic of eyes, do insects really see in that caleidoscope vision that they do on TV?
Well, arthropod eyes are called compound eyes. Each compound eye is made up of multiple ommatidia, each of which being like its own little eye.
Each ommatidium has a lens, light-sensitive visual cells, along with pigment cells to separate it from neighboring ommatidia.
Thousands of these combine to form sort of a mosaic. So yes, insects do see in a mosaic-like vision. This mosaic is kind of pixelated though, so it doesn't allow for sharp vision, but it is extremely good at detecting motion.
Now animals with really sharp vision are birds.
Birds have flatter eye shapes, unlike humans' round eye shapes, which let's more of their visual range be in focus. They can also change the shape of the lens much more rapidly than we can.
And birds of prey have a very high density of light receptor cells to maximize their visual acuity.
But that is only for "visual light." What if you could see heat... with your eyes closed?
Then you'd be a snake. Snakes can sense infrared radiation, more commonly known as heat. But they don't do it with their eyes.
Pitvipers, for example, have little pits on their face that can sense heat.
The pit is a deep pocket with a membrane stretched across it. This allows there to be air on either side of the membrane. The membrane is full of many heat-sensitive receptors, allowing them to sense heat.
But unlike light receptor cells, they don't detect the infrared light, they just detect the warming of the organ, which technically doesn't make this a vision super power, but I'll let it slide.
But what about the other end of the spectrum? What about Ultra Violet?
Well, enter the bee. Bees, like humans, have three types of cones and can see three types of colors.
Humans can see red, green, and blue light. But bees can see green, blue, and ultraviolet light.
They use this UV vision to see flowers as bright flashy landing pads, which makes getting nectar easier.
So to sum up, we may think we have the best eyesight, but we can only see a sliver of the world that the rest of the animal kingdom sees.
If you could have the vision of one of these animals or another that I didn't mention, what would it be? Let me know in the comments down below and thanks for watching, have a wonderful day.
Intro Music: Itty Bitty 8 Bit - Kevin Macleod
Background Music: Airport Lounge - Kevin Macleod
Outro Music: Long Stroll - Kevin Macleod
The Human Eye: http://www.allaboutvision.com/resources/anatomy.htm
Rods and Cones: https://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap_9/ch9p1.html
Infrared Sensing In Snakes: