Eyes Up Here Trivia Quiz

Answer: False

Not really, no. A true case of the eyes being 'up here', a snail's actual eyes are a small spot on the end of their eyestalks and, while these are an evolutionary trait designed to give a snail a better sense of its surroundings, they only help so much. The truth is that the snail's eye isn't capable of focusing what it sees at any distance, so much of what it's able to sense is a disparity between light and dark with no focus at all. Compared to a lot of invertebrates, its eyesight is very poor.

Slugs are, compared, quite similar, and their lack of shell actually makes them more prone to threats. Fortunately, both snails and slugs are likely to regrow their eyestalks entirely if damaged. They must be worth something.

Answer: Rectangular

There are actually quite a few animals with rectangular pupils, and this capability allows them to have better range of vision to avoid being caught out by predators. Horses, in particular, are large animals, but have minimal options in terms of being able to fight back or overtake other creatures, so defense mechanisms and early warning systems are a must. These types of pupils ultimately give horses (and sheep and goats) the ability to see more and with sharper clarity in the periphery of their vision.

Horse eyes are also one of the largest on any land mammal, and they're less 'up here' than they are 'out there'; horse eyes are positioned on the sides of their narrow heads. As such, they're able to see nearly 360 degrees. It's part of the reason why horse racers use blinders to narrow their steeds' fields of vision.

Answer: Three

This is an actual 'eyes up here' moment since, as you can see in the image, an alligator's eyes sit up higher than much of the rest of this reptile's head, an intentional evolutionary advantage that allows them to see above the surface of water while the rest of them lurks below.

This ultimately allows the alligator to stay cool and lie in wait for prey, but there's one more unique trait that allows them to commit to this: the nictitating membrane. What this means is that the alligator has one more transparent eyelid (on top of the two that it already uses) that allows it to continue to see without fully closing their eye while partially-submerged.

It's not alone in having this membrane-- a lot of domestic pets like dogs and cats, a number of birds, and many other amphibians use this trait, though maybe not to such a great effect.

Answer: No

Found throughout the waters of Central and South America, anableps are found in the saltier marshes and siltier waterways along the coastlines of places like Venezuela, the Amazon Delta, and Panama and, while you're not likely to see them below the water's surface, you might catch their shiny eyes peeking out. (Their eyes are up there!)

As to their name, you might believe they're wearing glasses or you might believe they actually have four eyes. The truth is more complicated; these fish have eyes that are large enough to be split by the water while swimming, and two separate retinas that allow them to see in the air and under the water. As such, each eye functions doubly, providing a field of view unimpeded by an inability to see one way or the other. Because of this (and other biological plusses), anableps can technically survive on land for a short time.

Answer: Concave

People, and most animals for that matter, have convex lenses/eyes, and this is because an eye that bulges outward allows for light to bend and create focus naturally. A chameleon's eye works the opposite way, and what an odd eye it is. By having a concave lens (ie. it bends inward), the light that hits the eye diverges, allowing the brain of a chameleon to see with higher magnification.

A chameleon's eyes are positioned on the side of the head ('eyes out there' instead of 'eyes up here', truly), and with the ability to operate them independently. With as much range of vision as they have, the ability to see in higher magnification across the board makes these reptiles extremely adept at locating insect prey while being able to assess their environment for predators and, if needed, spur on their natural camouflage.

Answer: Photoreceptors

How, you may ask, do they do it? Well, their eyes are 'up here', 'over there', and 'everywhere else' in a sense, since the sea urchin is able to sense and react to light based on countless photoreceptor cells found all over its body and spines. The creature has absolutely no eyes in the traditional sense, but the ability to register light and shadow through dermal sensation is what allows it to survive.

Sea urchins shy away from light naturally, so they make their homes in tight spaces and crevices close to or in water. They're surprisingly simple creatures when it boils down to it; there is no central nervous system in a sea urchin, so the nerves do all the work in allowing it to move, react, and survive. You could make the argument that it's just a big, spiky bundle of nerves...or one big eye. But let's not say that; it's weird.

Answer: Five

Starting with the eyes that are 'up here', the compound eyes are bulbous features on any dragonfly, and perhaps the most distinguishing feature of this unique insect. Composed of tens of thousands of individual ommatidia 'panels', these photoreceptor cells combine to create the unique patterns that form these organs.

The catch is that there are three other, simpler eyes on a dragonfly's body, and these are situated in front of and between the two larger compound eyes. While the larger eyes allow the dragonfly to have an amazing field of view that allows them to see above, below, and all around, the three smaller eyes are somewhat used for navigation and orientation, allowing for this large insect to balance and stabilize on a flat horizon when in flight. The brain ultimately uses all of this info to allow the dragonfly great control of its motion with all the perks.

Answer: Sand

Like horses, camel have eyes on the sides of their heads (not above them) but there are major differences between the two riding animals. Most horses around the world are a bit less well-suited to desert environments, but camels have evolved in many ways to thrive in them, and this is without even getting into the idea of storing water and fat in their humps.

Camel eyes don't have the same sort of range of vision as horse eyes, and it's due in part to their facial make-up, which is designed to protect the eyes from the harsh desert winds, sand, and tiny critters. In addition to being set a bit further into the skull, a camel eye has, like an alligator, a nictitating membrane to flush the eye of any particulates that get through (which is inevitable). But before all this, camels have two sets of thick eyelashes, there to prevent blowing sand from getting to the eye in the first place. The thick hairs extend to the inner ear as well. Ultimately, the camel needs to withstand a particularly annoying ecosystem, and it's hardier than most in its situation.

Answer: Four times as many

The mantis shrimp may seem like an odd creature to place focus on but, in reality, it has one of the most complicated and complex eye structures in the world (as far as we know). In addition to having independent eyestalks like a snail or a slug, its eyes are composed of photoreceptor cells like a dragonfly and they split into three separate divisions (yes, that's more than the bifurcation of the four-eyed fish).

Human eyes carry four photoreceptor types-- rods, and three types of cones that allow for us to see colours of varying wavelength ranges. The mantis shrimp has sixteen photoreceptor types; it can see in infrared, it can see in ultraviolet, and it can see in polarized light. It uses these capabilities to function as a species, as it's understood that, at least their ability to see in polarized light, allows them to affect their bodies and signal each other in ways that spur mating signals and warn one another of environmental dangers. And perhaps most interestingly, the eyes themselves are capable of assessing these signals, in a way that, in any other animal, would be comprehended by the brain.

Answer: They glow in the dark

If you took a typical thirty-centimetre ruler, you'd pretty much have the diameter of the giant squid's eye in hand. These colossal creatures, known for their already overwhelming size, have an almost comically-large eye size, which does help quite a bit when scanning the ocean for predators (and yes, they are considered prey creatures despite their size).

The glow-in-the-dark nature of the giant squid's eye is a by-product of bioluminescent glands known as photophores, which surround the lens of the eye and contain bacteria that create this effect. While one might assume that this allows pretty much anything to spot the giant squid from a distance, its own eyes can see very far, even in deep, dark, or murky water, allowing it to assess its surroundings, the circumstances surrounding it, and the distance they need to keep from larger creatures. It's theorized that the range of sight of the colossal squid developed through evolution to be just a touch further than whale sonar, keeping it out of reach if it's keeping tabs.