Inside the Glass..Frog!
Glass Frog Transparency Offers Insights into Blood Cell Storage and Camouflage
A recent study published in Science has revealed how the glass frog, a small amphibian native to Central and South America, achieves near-invisibility during rest by hiding nearly 90 percent of its red blood cells in its liver. This fascinating discovery sheds light on both biological camouflage and potential applications in medical science.
The researchers used high-resolution ultrasound imaging and light microscopy to observe living glass frogs (Hyalinobatrachium fleischmanni) in their natural habitat. They found that when the frogs are active, their blood flows normally throughout their bodies. But when the frogs rest and need to blend into their leafy environments, the red blood cells disappear from circulation and are packed tightly into the liver, which becomes reflective and opaque.
This process dramatically reduces the amount of red pigment visible in the body, making the frog almost entirely transparent apart from its bones and a few organs. The effect is not simply a matter of color change—it involves active biological control of circulatory patterns. The frogs manage to concentrate red blood cells without forming clots, a feat that challenges current understanding of clotting dynamics in vertebrates.
The implications go beyond amphibian biology. Understanding how glass frogs avoid clotting while storing red blood cells may inspire new strategies for managing blood storage in humans. This could lead to medical advancements in areas like trauma care, blood banking, and circulatory disorders.
Scientists believe this adaptation evolved as a survival mechanism to evade predators by becoming almost invisible against the green background of leaves. The research also highlights the importance of non-traditional model organisms in uncovering novel physiological mechanisms that have broad relevance.
Sources https://www.science.org/doi/10.1126/science.abn0544 https://www.nationalgeographic.com/animals/article/how-glass-frogs-hide-red-blood-cells-to-turn-transparent