Would you say this glass frog is half full or half empty?
Lack of pigmentation on the frogs' bellies allows observers to see their organs, bones, and muscles through the amphibians' skins. At least 138 species of glass frogs are known to exist in the rain forests of Central and South America.
Glass frogs live their entire adult lives in trees, and some species lay their eggs on leaves above streams. When the eggs hatch, the tadpoles fall into the water below, where they live until they sprout legs and hop back into the trees.
Amphibians, such as glass frogs, are considered indicator speciestheir population health reflects the overall condition of the environment. Many species of glass frogs are listed on the IUCN Red List of Threatened Species, because logging and farming are rapidly destroying their rain forest habitat.
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Photograph courtesy Ron D. Holt