The Glass Frog

Special Adaptation

As for the camouflage itself, it is clear that their transparent bellies and light-green skin blend in against leaves in the underbrush. Living in an environment where sunlight is scattered and shadows are uneven, the glass frog can utilize its size to prevent predators from seeing it. While other frogs can be seen from the underside of a leaf due to their dark colors and weight, glass frogs remain safe due to their completely transparent bellies (Naish). As such, predators would not even be able to see a shadow or silhouette on a leaf. While this illusion is powerful; their size makes it difficult for the frogs to escape when spotted. If caught unaware during the day, glass frogs have no method of fleeing quickly or fighting back. 

The organs within the frog can be easily seen through the transparent belly.