Have you ever wondered how animals see the world? Although we cannot actually see through another life form’s eyes (at least not yet), through science we can make a close approximation. Throughout the process of evolution, the eyesight of animals has developed in different ways. While our brains perceive reality in a 3 dimensional way, our eyes can only show us two dimensions. The depth that we all think we can see is merely a trick that our brains have learned; a byproduct of evolution putting our eyes on the front of our faces. The invention of different types of cameras and handheld flashlights also facilitate humans with the ability to observe things with different types of light filtration. For example, the UV spectrum; which animals like bees see with. Here are some incredible images that reveal how different animals see the world.
1. Birds: Humans (left), Birds (right)
The image on the left shows the human perception of a peacock feather, while the right side shows a bird’s perception. While humans have about 200,000 receptors per mm2, birds have 2 to 5 times this amount. Out of all its senses, birds rely tremendously on their vision. Since their reliance on vision is so significant, birds have developed unique characteristics in processing these types of information over 150 million years of natural selection.
Avian eyes occupy a much larger volume of their head than do the eyes of other mammals. This helps them to find food, identify potential mates, escape from predators, and aid in general orientation. Most birds can also see the ultraviolet spectrum.
2. Dogs: Humans (left), Dogs (right)
Dogs only have two cones, blue and yellow but not red and green. Their vision can be compared to a human who is color blind. Humans see the world in color because we have three types of color receptor cells, or cones, in their eyes. These are sensitive individually to red, green, and blue light, and the different intensities and proportions of those three colors as seen by our eyes are put together by the brain to create the full-color world as we know it.
For dogs, their color vision is most similar to a human with red-green color blindness, although there are other differences. Dogs are also less sensitive to variations in gray shades than humans are, as well as only about half as sensitive to changes in brightness. They are also nearsighted to varying degrees. However, when it comes to visual abilities, dogs outperform humans. They are also more sensitive to motion at a distance; anywhere from 10 to 20 times more sensitive than humans. Their vision is also well-suited for hunting during dawn and dusk.
3. Snakes: Humans (left), Snakes (right)
Snakes have both a daytime and night-time pair of eyes. Reptiles that hunt during the day, have lenses that can filter out ultraviolet rays to sharpen their vision. Nocturnal snakes on the other hand have a distinct set of eyes that actually let in as much ultraviolet light as possible. They can see some color, but also infrared, with extremely sensitive infrared sensors located on their heads. Snakes are capable of picking up infrared signals from warm objects in their surroundings.
Meanwhile, rattlesnakes have one small pit on each side of its head. These pits are filled with thousands of receptor cells which are actually microscopic-sized infrared sensors. While the size of the receptors are comparatively small, they are 10 times more sensitive than the best artificial infrared sensors that mankind has managed to artificially build.
4. Bees: Bees (left), Humans (right)
Unlike humans, bees have color receptors for blue and green but they also the UV spectrum. The sensitivity to UV light is important for bees since it helps them to detect patterns on flower petals and find nectar to make honey. They not only see flowers differently than we do but can see ultraviolet light patterns at the center of the flower that are a different colors than the rest of the flower (as illustrated in the picture above).
The color patterns in the petals are vital for the bees. As they hover above, these patterns allow them to pinpoint the flower with the most nectar and pollen. You could say that the UV patterns are like landing zones, directing them to the best source for nectar.
5. Bats: Humans (left), Bats (right)
Bats are a fascinating group of animals. They are one of the few mammals that can use echolocation to navigate. Echolocation is a neat trick that sends sound waves to determine the size, shape and distance of an object. Bats use the technique to not only navigate, but also to hunt. While most bats produce echolocation sounds by contracting their larynx (voice box), some species click their tongues and emit through their mouths.
While echolocation is a neat trick, there are some species of bats (such as the greater mouse-eared bat) that use polarized light to navigate. The light waves are parallel to each other and vibrate in a single plane. These bats utilize the scattered polarized rays at sunset to calibrate their internal compass. This allows them to fly in the right direction. Researchers suggest that these bats are using polarized light to begin their journey, then the position of stars and the Earth’s magnetic field to find their way back to their resting place.
6. Butterflies: Humans (left), Butterflies (right)
Butterflies may not have a human’s sharp vision, but their eyes beat us in other ways. Their visual fields are larger, they’re better at perceiving fast-moving objects, and they can distinguish ultraviolet and polarized light. Like Bees, this enables them to detect a flower’s stash of pollen. Each of their eyes contains at least 15 different types of photoreceptors; the light-detecting cells required for color vision. However, they only have 0.04 the visual acuity of humans. Still, their eyes allow them to spot a small coin at a distance of 50 cm.
The structure of a butterfly’s eye is very different from that of a human eye. Their eyes are comprised of many facets, and in the case of the swallowtail, their eyes consists of an incredible 12,000 facets. Each facet collectively perceives a single view of the world, like a digital camera.
7. Cats: Humans (top), Cats (bottom)
Cats are also color blind in a similar way to dogs, but they have better peripheral and night vision than humans. The biggest difference between human vision and cat vision is in the retina. They are also incapable of viewing objects far away. However, when it comes to seeing in the dark, their eyes have extraordinary capabilities. Cats (and dogs) have a high concentration of rod receptors and a low concentration of cone receptors, while humans have the opposite.
Cats cannot see the same richness of hues and saturation of colors that we can. They are also nearsighted, which would be well-suited for hunting and capturing prey. Their ability to see in the dark is due to the higher number of rods in their retina that are sensitive to dim light. They can see using roughly one-sixth the amount light that humans require (illustrated in the picture above).
8. Cuttlefish: Cuttlefish (left), Humans (right)
The vision of a cuttlefish is more blurry than that of a human and they are also completely color-blind. The pupil of a cuttlefish is shaped like a W, making it look alien-like as it pursues prey in the ocean. They communicate with one another by producing polarization patterns on their skin. Cuttlefish see each other in shades of gray with the polarization information overlaid.