By César Barrio Amorós
A type of frog not very well known is the glass frog. Glass frogs are small and very beautiful; they are an important addition to my night tours, mainly because they are not easy to find. They are completely transparent on their belly sides, which means you can see their internal organs (such as the heart, lungs, liver, and stomach) through their skin.
That’s the reason they are called “glass frogs.” Some of them sing in a way that resembles the sound of a fork reverberating in a wine glass. They are exclusively nocturnal and live by the mountain streams. Some of them sing hiding under the leaves, and others do it while exposed.
Typically, the males of some species take care of the eggs laid by the females under the surface of a leaf. Once the embryos mature, they drop down into the stream of water to complete their cycle becoming the small glass frogs enhancing the Costa Ballena’s nights.
During the day, they sleep under green leaves; they are so transparent that nobody can see them. Going unnoticed is their best defense. In just one ravine among the mountains surrounding Costa Ballena, you may find up to five different species living together.
On Docfrog’s Facebook page, you can see pictures of glass frogs in their environment, and a video of one of them singing.