{"id":24273,"date":"2023-01-30T16:39:47","date_gmt":"2023-01-30T15:39:47","guid":{"rendered":"https:\/\/www.discoverwildlife.com\/?p=73778"},"modified":"2023-01-30T20:37:05","modified_gmt":"2023-01-30T19:37:05","slug":"why-do-iguanas-have-three-eyes","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcwildlife\/rss_feed\/why-do-iguanas-have-three-eyes\/","title":{"rendered":"Why do iguanas have three eyes?"},"content":{"rendered":"

The iguana’s third eye is a useful way of detecting danger says Alex Morss <\/p>

By Alex Morss\n \t\t<\/p>

Published: Monday, 30 January 2023 at 12:00 am<\/p>

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F<\/span>ossils<\/a><\/strong> reveal that many animals once had a third eye on top of their heads. It has disappeared in mammals and birds, but some reptiles and amphibians still have this residual \u2018parietal\u2019 eye.<\/p>\n

In iguanas, it is often visible as a grey spot. You can also make it out (albeit less clearly) in some other lizards, such as skinks, anoles and young tuataras, as well as in frogs and salamanders.<\/p>\n

Mostly, it is not functional and fades under skin and scales as animals mature. However, a few lizards use their third eye to detect blue and green light and \u2018read\u2019 the time of day, like a clock.<\/p>\n

By sensing shadows and light changes, the eye can detect danger and may also act as a navigational compass. It uses chemicals to detect light, unlike other vertebrate eyes, which use rod cells or cone cells.<\/p>\n

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