Beastlypedia
A glass frog on a backlit green leaf with its translucent underside showing internal organs

Beastfile · Amphibians

Glass Frog

Centrolenidae

You can watch its heart beat through its own skin.

Overview

Glass frogs are small Central and South American tree frogs, usually lime green from above and almost transparent underneath. Turn one over and the abdominal skin shows the heart, liver and looping gut directly. The transparency is not a trick of the light: these frogs genuinely lack the pigment layer that makes most animals opaque on the belly. Research has shown the effect works as camouflage from below by softening the frog outline against a backlit leaf, rather than by making it invisible outright. Males of many species guard the eggs, which are laid on leaves overhanging water so the tadpoles drop straight in.

A glass frog resting on a wet leaf, its translucent skin catching the light

Origin

Humid montane and lowland rainforest from southern Mexico through Central America and into the Andes and Amazon basin.

Habitat

Rainforest

Notable Traits

  • •Transparent abdominal skin showing heart, liver and gut
  • •Bones appear green in some species
  • •Eggs laid on leaves above water so tadpoles drop in on hatching
  • •Males of many species guard the clutch
  • •Rarely larger than three centimetres

Conservation

Varies sharply by species; several are threatened. Glass frogs depend on clean, fast streams and intact forest, which makes them sensitive to deforestation, water pollution and the amphibian chytrid fungus.

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