Tiny transparent creatures

Picture a little green frog with skin so transparent you can actually see its heart beating!

The glass frog is one of the coolest animals on the planet! Living in rainforests, glass frogs look really cool and they have bellies so clear, you can actually see inside of them.  Although they live in the tall trees in Central and South America, you hardly ever see them because they can be so good at camouflaging themselves. Scientists are still learning all the secrets about this amazing animal: the glass frog.

Glass frogs are very cute and beautiful, almost like something magical. They are very small and can fit easily in a person’s hand. Glass frogs are generally small. They usually range from 1.9 centimeters (0.75 inches) to 7.6 centimeters (2.99 inches) in length. Their backs are bright green, and their bellies are clear, so you can see their organs inside. Some glass frogs are white with yellow spots that look like eggs. For male frogs, these spots help trick predators when they are guarding eggs. They will usually lay eggs on leaves above water, when the eggs hatch the larvae will drop into the stream below.

Don’t their eggs look like Dot candy?

Glass frogs are very rare and hard to find. Even scientists who study them in rainforests are still finding new kinds. Their see-through belly helps them hide better: for the top view, when they pull their legs close to their body, it makes their shape harder to see, so birds have a harder time spotting them. In the rainy season, when they come down from the trees to mate, you can even see the eggs inside the female’s body before she lays them.

Glass frogs have beautiful big eyes; it looks like they have a thin layer of membrane covering their eye. They have many varieties of eye colors but the most common one is gold. There are different types of glass frogs, like the Tukeit Hill, the Chimerilla, the La Palma, and the ghost glass frog.

The ghost glass has big eyes with blue or black lines with a black oval in the center of the eye. There are many other types of glass frogs that have different eye colors making it more exciting to learn more about them! Some have big, round, golden-green eyes with black centers, draped with a golden membrane.

Can you believe the sheer size of these orbs? Their eyes sit on top of their heads and can move in different directions. They have great eyesight, which helps them catch insects to eat.

The first identified species in the family Centrolenidae was a giant Centrolene geckoideum that was discovered in 1872 by Marcos Jiménez de la Espada from a specimen in the northeastern part of Ecuador.

Here’s a picture of the actual specimen:

From then until the 1950s, other investigators like G.A. Boulenger, G.K. Noble, and E.H. Taylor described many more species but usually grouped them with tree frogs in the relatives Hyalella or Hyla. Edward H. Taylor was the first researcher to clearly show the family of Centrolenidae in 1945. From the 1950s through the 1970s glass frogs were mainly discovered in Central America, primarily Costa Rica and Panama by researchers Taylor, Julia F., and Jay M. Savage, while only a few from South America. All of this changed in 1973 when John D. Lynch and William E. Duellman wrote a major review of Ecuadorian glass frogs that revealed there were many more species actually living in the Andes. Later with researchers including Juan Rivero, Savage, Duellman, Lynch, Pedro Ruiz-Carranza, and José Ayarzagüena, there would be additional species discovered particularly in Central America, Venezuela, Colombia, Ecuador, and Peru.

Glass frogs may be confused with a few green frogs from the genus Eleutherodactylus and some Hylidae tree frogs. The important difference is that these frogs have eyes that point out laterally.

Although glass frogs have large eyes, they are circular and point straight ahead, as you can see from the pictures above.

Glass frogs are incredibly unique and rare species, and researchers continue to learn more about them!