10 Animals With Incredible Eyes

Eyes are important organs for many living creatures. Some creatures have amazing and complex eyes. Here are 10 animals with incredible and strangest eyes.


10. Tarsier

Tarsier

The tarsier has enormous eyes, the largest of any mammal, relative to body size. Each eye is weighing more than its brain. These enormous eyes can’t be turn in their sockets because they are fixed in the skull. To compensate for this, the tarsier has a very flexible neck, and can rotate its head 180 degrees, just like an owl, to scan for potential prey or predators.
The tarsier has extremely acute eyesight and superb night vision; it has even been suggested that they may be able to see ultraviolet light. On the other hand, they seem to have very poor color vision, as is the case with many nocturnal animals (including house cats and owls, for example). This small nocturnal primate can be found in the rainforests of South Eastern Asia.

9. Chameleon

chameleon

Chameleons have very unusual eyes. Their eyelids are fused, and cover almost the entire eyeball, except for a small hole to let the pupil see through. Each eye can be moved independently from the other, which means that the chameleon has a full 360 degree field of vision so the chameleon can scan for prey and potential threats at the same time.
When the chameleon sees a potential prey, it focuses both eyes in the same direction, gaining stereoscopic vision. It’s very important because the chameleon captures prey by shooting out its tongue at high speed, a technique that requires a very precise distance and depth perception. Chameleons have very sharp eyesight, being able to see an insect several meters away, and just like the tarsier, they can see ultraviolet light.


8. Dragonfly

dragonfly

Dragonfly’s eyes are so big that they cover almost the entire head, giving it a helmeted appearance, and a full 360 degree field of vision. These eyes are made up of 30,000 visual units called ommatidia, each one containing a lens and a series of light sensitive cells. Their eyesight is superb; they can detect colors and polarized light, and are particularly sensitive to movement, allowing them to quickly discover any potential prey or enemy.
Dragonflies also have three smaller eyes named ocelli which can detect movement faster than the huge compound eyes can. These ocelli quickly send visual information to the dragonflies’ motor centers, allowing it to react in a fraction of a second and perhaps explaining the insect’s formidable acrobatic skills. Some wasps and flies have ocelli too, but Dragonflies do have the most developed ones.


7. Leaf tailed gecko

leaf tailed gecko

Leaf tailed geckos have pretty surreal-looking eyes. Their pupils are vertical and have a series of “pinholes” which widen at night, allowing these lizards to pick up as much light as possible. These eyes also have many more light sensitive cells than human eyes, giving the animal the ability to detect objects and even to see colors at night.  The Leaf Tailed gecko and other nocturnal gecko species can see up to 350 times better than human can in dim light.
Leaf tailed geckos also have a series of strange, intricate eye patterns, which provide camouflage. They lack eyelids; their eyes are protected by a transparent membrane. They are often seen cleaning this membrane with their tongue.


6. Colossal squid

colossal squid

The Colossal squid is the largest invertebrate known to science; it also has the largest eyes in the animal kingdom. Each eye can be up to 30 cm across. These huge eyes allow the squid to see in dim light conditions, very useful for hunting at 2000 meters below the surface.
The Colossal squid has stereoscopic vision, having a greater ability to judge distances. Even more amazing, each eye has a built-in “headlight”, an organ known as a photophore which can produce light so that whenever the Colossal squid focuses its eyes to the front, the photophores produce enough light for the squid to see its prey in the dark.


5. Four eyed fish

four eyed fish

Despite their name, four eyed fish have only two eyes. These eyes are divided by a band of tissue and each half of the eye has a pupil of its own. This allows the four eyed fish to see perfectly both above and below the waterline at the same time, scanning for both prey and predators. The upper half of the eyeball is adapted to vision in air, while the lower half is adapted to underwater vision.
Although both halves of the eye use the same lens, the thickness and curve of the lens is different in the upper and lower eye halves, thus correcting for the different behavior of light in air and water. This means that when the four eyed fish is completely submerged, the upper halves of the eyes are out of focus. Fortunately, the fish spends almost its entire life in the surface, and it only has to dive completely once in a while to prevent the upper halves of the eyes from dehydrating. Four eyed fish can be found in Mexico and Central America, as well as Northern South America.


4. Stalk eyed fly

stalk eyed fly

Stalk eyed flies get their name from the long projections from the sides of the head with the eyes and antennae at the end. Males’ eyestalks are longer than females and it has been confirmed that females prefer males with long eyestalks.
Males during mating season often stand face to face and measure their eyestalk’s length; the one with the greatest “eye span” is recognized as the winner. They also have the extraordinary ability to enlarge their eyestalks by ingesting air through their mouth and pumping it through ducts in the head to the eyestalks.



3. Spookfish

spookfish

The spookfish has some of the most bizarre eye structures known to science. Each eye has a lateral swelling called a diverticulum, separated from the main eye by a septum. The main eye has a lens and functions in a similar way to other animal eyes while the diverticulum has a curved, composite mirror composed of many layers of what seem to be guanine crystals.
This “mirror” is superior at gathering light than the normal eye; the diverticulum reflects light and focuses it onto the retina allowing the fish to see both up at down at the same time. This deep water, ghostly-looking fish is the only vertebrate known to use a mirror eye structure to see, as well as the usual lens. Spookfish live at a depth of 1000-2000 meters feeding on small crustaceans and plankton.


2. Ogre faced spider

ogre faced spider

Spiders are popularly known for having many eyes. The Ogre-faced spider has six eyes, but it looks as if it only had two because the middle pair is greatly enlarged. This is an adaptation for a nocturnal lifestyle; ogre faced spiders have superb night vision not only because of their huge eyes, but because of an extremely light sensitive layer of cells covering them. This membrane is so sensitive. It’s destroyed at dawn and a new one is produced every night.
Ogre faced spiders can see perfectly at night even though they lack tapetum lucidum, a reflective membrane that helps others spiders (and other predators such as cats) to see in low light conditions. Scientists believe that ogre faced spiders can see up to 100 times better than humans at night.


1. Mantis shrimp

mantis shrimp

The mantis shrimp is not actually a shrimp, but a different kind of crustacean from the Stomatopoda order. The mantis shrimp is so aggressive and has formidable weaponry. They have an extremely sharp and powerful claw that can split a human finger in two or even break a glass aquarium with one single strike. The mantis shrimp are voracious predators found mostly in tropical waters.
Their eyes are compound, like those of the dragonfly, but they have a far smaller number of ommatidia (about 10.000 per eye). However, in the mantis shrimp each ommatidia row has a particular function. For example, some of them are used to detect light, others to detect color, etc.
Mantis shrimp have much better color vision than humans, as well as ultraviolet, infrared and polarized light vision, thus having the most complex eyesight of any animal known. Their eyes have 12 types of color receptors, whereas humans have only three. The eyes are located at the end of stalks, and can be moved independently from each other, rotating up to 70 degrees. Interestingly, the visual information isn't processed by the brain but the eyes themselves.
Even more bizarre; each of the mantis shrimp’s eyes is divided in three sections allowing the creature to see objects with three different parts of the same eye. In other words, each eye has “trinocular vision” and complete depth perception, meaning that if a mantis shrimp lost an eye, its remaining eye would still be able to judge depth and distance as well as a human with his two eyes. Scientists are only starting to understand the mysteries of Stomatopod vision; for the moment, we can only imagine what the world really looks like to a mantis shrimp.

Source: 10 Animals With Incredible Eyes