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11 intriguing transparent animals

By: Bryan Nelson on Jan. 24, 2011, 11 a.m.
A glass frog seen from below

Photo: J.P. Lawrence/Shutterstock

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Glass frogs

Don't worry … you aren't having a flashback to high school biology class. These amphibians of the family Centrolenidae< are called glass frogs because the abdominal skin of many species is highly transparent, and viewing them from underneath is like looking at an MRI.

Many of the frogs' internal organs, such as the heart, liver and gastrointestinal tract, are on display. Found in the jungles of Central and South America, these animals are mostly arboreal, meaning they live primarily in trees.