Invisible frog
Being both vital for life and the most delicate parts of our bodies, it’s no surprise that we don’t often see our internal organs, or those of other animals. Most bodies are built with them hidden inside multiple protective layers of skin, tissue and bone. But what if these layers were see-through? Looking at a glass frog from above, you may not see anything out of the ordinary compared to other frog species, being the same shape and that classic green colour we often associate with them. But if you were to look at its underbelly, its shape would suddenly fade into the background. A tiny, fast-beating heart would be the first thing to catch your eye, along with a long, red vein. Next to this a section of squirming intestines work to break down food. These amphibians have evolved to have an extremely thin, translucent skin. While this puts its entire internal anatomy on full display, its overall shape becomes invisible to predators. Some glass frogs have this skin on both the back and belly, but the majority are only see-through from below. How does the frog have any advantage if the transparent area is always facing the ground? This all comes down to their habitat. Living in the rainforests of Central and South America, they spend much of their time perched on leaves. Submerged in luscious greenery, their vibrant topcoats are ideal for camouflage. Meanwhile, their transparent base means that while they sit high on a tree’s leaf, with light shining from above, their silhouette is much less visible from below.