Humans may be proud of their eyes through which they adore the rich and colorful world, but have we ever wondered how vibrant and remarkable animals eyes can be?
They have two large compound eyes on either side of their head. Each eye is actually composed of thousands of smaller lenses known as ommatidia. These form large globe-like eyes and give them a pixelated view of the world.
Three smaller eyes at the top of their head called ocelli which have single lenses serve as a kind of navigation system and also help them to see ultraviolet light. Bees’ color perception is different from ours. They can see into the ultraviolet range, but to them, red is black.
Honeybees are far better than we are at detecting motion. They clearly can detect a motion that happens in 1/300th of a second. If a movement takes 1/300th of a second, a bee can see the beginning and end of that movement. We humans would never see it. For us to register motion a movement must take longer than 1/50th of a second. A field of flowers or the blossoms of a tree may look still to us, but to the bees, those flowers are moving.
2. Jumping spiders.
They have four pairs of eyes- two large principal eyes with highly telescopic vision, a pair of smaller forward-facing eyes with good binocular vision and two pairs of small lateral eyes. The large tubular front eyes contain four distinct photoreceptor layers that can see both visible and ultraviolet light. Th spider uses its lateral eyes to sense the motion of an object.
3. Mantis shrimp.
A marine animal that’s neither a mantis nor a shrimp, but a close sibling of crabs and lobsters.This group of marine crustaceans may be well known for their impressively rapid and powerful punches. But their vision also holds the most complex visual system of all animals. They have eyes that contain 12 to 16 different types of photoreceptors in its midband and can see UV, visible and polarized light. Each eye is also able to rotate independently and perceive depth.
Like us, mantis shrimps see colour with the help of light-sensitive proteins called opsins. These form the basis of visual pigments that react to different wavelengths of light, allowing us to see different colours. If a mantis shrimp has six UV receptors, it should have at least six opsins that are sensitive to different flavours of UV. Many marine animals have one or two MAAs (mycosporine-like amino acid). They use these as sunscreens to block UV from reaching their skin and eyes and causing damage that could eventually lead to cancer. The mantis shrimps also use MAAs to block UV but for a unusual purpose: to turn their eyes into astonishingly sophisticated UV detectors.
4. Four-eyed fish.
Found in Mexico, Central America and northern South America, four-eyed fish belong to genus anableps. despite their name, four-eyed fish have only two eyes, divided by a band of tissue and each half of the yes have a pupil of its own. This bizarre adaption is due to the difference in thickness and curve of the lens in the upper and lower eye halves thus correcting for the different behavior of light in air and water, allowing them to see perfectly.
These fish are members of the Anableps genus. There are three approved species. The Four-Eyed Fish, A. anableps, is the one most commonly seen in the aquarium hobby. The species Anableps microlepis, usually known as Foureyes, is sometimes available and very similar to A. anableps, but it lacks the white stripe on the top of its body. The Pacific Foureyed Fish, Anableps dowei, is very rare. Other common names A. anableps are known by including Anableps, Largescale Foureyes, Star Gazer, Four-eye, and Striped Foureyed Fish.
The A. anableps are an unbelievable species for an aquarist with some experience to keep. They are freshwater fish, but frequent river estuaries and mangroves swamps where the ebb and flow of the tide is constantly changing the salinity. They do best in a low-salinity, brackish aquarium. They are also schooling fish, happiest in groups of 6 or more. They should never be kept singly or even in pairs.
Goats have rectangular pupils, like many other herbivores, it helps them to see almost entirely around their bodies: effectively keeping the eye sits nearly parallel to the ground at all times, to watch their predators even when chewing down- no matter what the position of their heads. They can rotate more than 50 degrees per eye, the researchers say, which is 10 times of the human eye.
Feature image: npr.org