Amitav Sen says:
~ Chameleons ~ are famous for their ability to change color, an ability that helps them communicate and express their
intentions, or mood, to other chameleons (only a few species use color-changing as camouflage). These lizards
also 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, and so the chameleon can scan for
prey and potential threats at the same time. This also means that the chameleon has a full 360 degree field of
vision.
When the chameleon sees a potential prey (usually an insect, although the largest species are known to devour
mice and other small vertebrates), it focuses both eyes in the same direction, gaining stereoscopic vision – very
important if we consider that 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.
Amitav Sen says:
The ~ dragonfly, ~ possibly the most formidable aerial hunter among insects, also has some of the most amazing eyes in the animal world. They 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.
Some dragonfly species that hunt at dusk can see perfectly in low light conditions, when we humans can barely
see anything. Not only that; 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. Although dragonflies are not the only insects with ocelli (some wasps and flies have them too), they do
have the most developed ones.
Amitav Sen says:
~ 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.
To give you an idea of the gecko’s amazing night vision, let us just say that, while cats and sharks can see six and
ten times better than humans, respectively, the Leaf Tailed gecko and other nocturnal gecko species can see up to
350 times better than we can in dim light!
Leaf tailed geckos also have a series of strange, intricate eye patterns, which provide camouflage. These lizards
lack eyelids; their eyes are protected by a transparent membrane, and geckos are often seen cleaning this
membrane with their tongue.
Amitav Sen says:
~ Stalk eyed fly. ~
These small but spectacular creatures are mostly found in the jungles of South East Asia and Africa, with a few
species also found in Europe and North America. They get their name from the long projections from the sides of
the head with the eyes and antennae at the end. Male flies usually have much longer stalks 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.
Male stalk eyed flies 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. They do this mostly during mating season.
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