As the sun glistens on rainforest leaves, a snake slithers through the trees. It writhes around branches hunting for a tasty snack. A frog seems like a good choice, especially a sleeping one. This delicious reward would offer minimal resistance, but the snake faces one problem—finding a frog. The species hyalinobatrachium fleischmanni, more commonly known as the glass frog, is frequently persecuted by these wriggling reptiles.
Glass frogs inhabit the mid-elevation rainforests of Central and South America. One of the glass frog’s main predators are snakes who wander through trees perusing their branches and leaves for food. Measuring only .8 of an inch to 3 inches in length, the glass frog is frightfully smaller than the snakes who seek to swallow them. Snakes love to prey on glass frogs, but God has equipped them with a unique and dazzling defense mechanism.
Glass frogs are nocturnal, meaning they sleep during the day and are awake at night. They are most vulnerable to attacks from predators during their slumbers. However, while at rest, the skin on their belly becomes translucent enabling them to blend in with the leaves they sleep on. The skin covering the top of a glass frog is green, which is an important part of its camouflage when combined with its clear stomach.
If a glass frog is still green on top, how does the adaptable coloring of its stomach allow it to camouflage? Researcher James Barnett at McMaster University discovered that glass frogs could adjust their brightness to more closely match the shade of the leaf they were sitting on. He also discovered that the legs of a glass frog were more translucent than the rest of their bodies, which distorts the outline of their body on a leaf. “Visual systems are very sensitive to edges where two different colors meet, and thin, highly contrasting edges are particularly conspicuous,” he commented. “By having translucent legs and resting with the legs surrounding the body, the frog’s edge, where it meets the leaf, is transformed into a softer less contrasting gradient, blending the frog and leaf together more smoothly.” This trait of camouflage is called “edge diffusion.”
Clearly a glass frog’s translucent underside is crucial to its ability to camouflage, but how does a glass frog make its underbelly translucent? The difficulty in becoming translucent lies in the red blood cells prevalent in the glass frog’s circulatory system. These red blood cells absorb green light whereas plants and other green vegetation common in rainforests reflect green light. This means that the red blood cells within the glass frog’s circulatory system are extremely visible against vivid green leaves. To combat this, the glass frog becomes translucent by hiding 90 percent of its circulating red blood cells in its liver and shrinking the size of its liver by roughly 40 percent. In this state, the glass frog camouflages impeccably with its surroundings and its obscurity protects it from predators.
Their transparent bellies also allow us to see their bones, liver, heart, egg sac and intestines clearly without dissecting them. This rare feature permits scientists to observe the inner workings of a glass frog in real time.
These little amphibians reveal God’s creative genius. God loves variety in His creation, and He created the glass frog to be the only land animal with transparent skin. Not only does its clear underbelly provide a rare glance into the inner workings of this species, but it serves as a remarkable defense against outside attacks. Paul wrote in Romans 1:20, “For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:” God uses His creation as a tool to reveal His power. Learning about God’s creation should leave us in awe of His ability. It is one of the greatest proofs of God’s existence and the veracity of the Bible. Studying the glass frog and other unique creatures can help us prove God’s existence and marvel at His astounding ingenuity.