Glass frogs have highly translucent skin on their undersides, allowing you to easily see their beating hearts, pumping intestines, and developing eggs without having to dissect them at all.

A closer look

Glass frogs have highly translucent skin on their undersides, allowing you to easily see their beating hearts, pumping intestines, and developing eggs without having to dissect them at all. To avoid detection while sleeping on leaves, these incredible amphibians hide their red blood cells inside their livers to make themselves almost entirely transparent and practically invisible to passing predators. This is an absolutely brilliant evolutionary defense mechanism, though it is deeply unfortunate that they are constantly putting their internal organs on display for the entire rainforest to aggressively judge. Imagine if human beings became completely see-through every time we took a nap, forcing everyone around us to visibly witness exactly how poorly our digestive systems are handling that late-night pizza