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December 05, 2016
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Nature’s vision: the ‘eyes’ have it

Spiders are usually equipped with four pairs of simple eyes. The eye placement varies with species. On this jumping spider (photographed on a friend’s knee), the two large eyes that are facing front have the best acuity and even have telescopic ability to spot distant prey. The smaller ocelli have less resolution and serve as protection from side and rear attack.

October 20, 2011

If we see a bird or some other creature, and it is close enough, there is something that usually catches our eye early in our observation: the eyes. In nature, there are many adaptations of vision. Earthworms have simple eyes (ocelli) that are able to detect light and dark, while eagles and hawks have single lens eyes with visual acuity five times greater than a human. (An eagle has five times the density of vision cells at the central focus area of the retina than humans do.)

Each animal species in its habitat requires different vision adaptations in order to survive and reproduce. Look at the images to get an “eyeful” of these varied vision adaptations.