It may look like an eye, but it's actually a colourful eye-like spot on the tail fan feather display of a male peacock. Natural selection favours showy male birds, when the males are competitive and promiscuous (mating with more than one female). Female peacocks are more drab, making them more camouflaged as they sit on the nest.
	Planaria (genus Dugesia), the "cross-eyed" flatworm has two ocelli or eyespots composed of cells full of photosensitive pigments. These eyespots allow Planaria to perceive and react to light and they generally tend to move away from white light. This is why you will find them hidden beneath rocks and weeds in your local ponds and streams.
	The Coronet Fish is a long slender fish found in tropical waters. It generally travels slowly or hides among the coral heads, poised for a quick attack on other small fish that make up its prey. The eyes are relatively large, indicating their importance in finding prey and avoiding predators. Coronet fish can be distinguished from trumpet fish by the long extension of the lower lobe of the tail fin.
	Mantis Shrimp. The Stomatopods, or mantis shrimps have the most highly developed compound eyes of any crustaceans. These eyes have abilities to accurately detect motion and depth of a prey, and mantis shrimps are effective predators on a variety of fish and other prey. There are two styles of predation, and mantis shrimps are called accordingly 'spearers' or 'thumpers'.
	Euglena (50-100 micrometers long) is a photosynthetic protist with a distinct eyespot or stigma. Its green color comes from the chlorophyll in its chloroplast organelle. So, this is the closest thing to a plant with eyes. The stigma is a region of photosensitive pigments for light reception. Euglena displays phototaxis - a reaction to light and uses its flagella to either move towards or away from the light, depending on the light intensity.
	The gecko has one of the most unique and efficient pupil designs in the animal kingdom. As a primarily nocturnal animal, its eyes are highly sensitive to light so that bright daylight must be blocked. The gecko has a stenopeic pupil, a vertical slit lined with notches on each margin. When the pupil is entirely closed, tiny pinholes allow light to pass through to the retina creating sharp overlapping images.
	Praying mantis. One of the more sophisticated eyes in the Class Insecta belongs to the praying mantis. These animals are efficient predators, a lifestyle that has led to the evolution of refined depth-perception and visual acuity.

Back to our gallery about eye diversity and evolution - Who's Eye Is It Anyway?