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This Freaky Frog Is So Transparent You Can See Its Internal Organs

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Introducing Hyalinobatrachium yaku, a newly-discovered species of glassfrog that lives in the Amazonian lowlands of Ecuador. Like other glassfrogs, it features transparent skin on its belly, but this tiny critter takes things to another level by exposing the entire contents of its underside—heart and head included.

A new study published in ZooKeys describes the frog, which was discovered by Juan M. Guayasamin from the Universidad San Francisco de Quito in Ecuador. The distinctly Kermit-like creature features dark green spots at the back of its head and back, and measures just two centimeters in length. The males of H. yaku use a long call to attract mates, which they do from the underside of leaves. But this frog’s most notable feature is its translucent pericardium, a membrane enclosing the heart which extends from its belly all the way up into its chest and lower jaw.


Looking at its underside, you can see the frog’s kidneys, urinary bladder, reproductive system, and most remarkable of all, its heart. Many glassfrogs, such as C. resplendens, H. munozorum, and T. midas, have transparent bellies, but H. yaku features one of the clearest transparent undersides ever seen in a glassfrog species. Scientists aren’t sure why the bellies of glassfrogs are see-through, but it may help them avoid or confuse predators.


Guayasamin’s team found the new species at three distinct locations in Amazonian Ecuador, all within 65 miles (110 km) of one another. The populations exhibited similar physical characteristics, but distinct behaviors. In two of the locations, the frogs were spotted underneath leaves in slow moving rivers. In the third location, where human activity is rampant, the frogs were seen perching on leaves of small shrubs, ferns, and grasses. The glassfrogs in this third location were as far as 100 feet (30 meters) from the nearest stream, which they need to reproduce.

Sadly, these fascinating amphibians threatened by human activity. Oil extraction in the region, and related water pollution, road development, habitat degradation, and isolation, are making it exceptionally difficult for this delicate species to thrive.

“Considering the current scenario of development in the Ecuadorian Amazon, alternatives that contemplate both conservation and different levels of exploitation have been put forward by the scientific community,” write the researchers in their study. “These alternatives need to be seriously considered, especially when biodiversity research and conservation are clearly identified, at least in theory, as priorities for the Ecuadorian Government.”