Global Animal Guide Wildlife Encyclopedia
Tiny translucent glass frog on a leaf with internal organs visible through its skin
Amphibian Least Concern

Glass Frog

Hyalinobatrachium valerioi

Quick answer

Glass frogs are small tree frogs of Central and South American rainforests, famous for the translucent skin on their bellies that reveals their internal organs and beating heart. They are nocturnal, arboreal, and care for their eggs on leaves above streams. Most species live around 10 to 14 years.

Glass Frog facts at a glance

Key facts about the Glass Frog
Scientific name Hyalinobatrachium valerioi
Diet Insectivore (small insects, spiders)
Habitat Streamside vegetation in humid rainforest
Lifespan About 10–14 years
Weight Around 5 g (0.2 oz)
Size 2–3 cm (0.8–1.2 in) body length
Conservation status Least Concern (IUCN)
Scientific classification
Kingdom Animalia
Phylum Chordata
Class Amphibia
Order Anura
Family Centrolenidae

Where it lives

Humid rainforests near clear streams across Central and South America.

Behavior and transparency

Glass frogs are named for the translucent skin on their undersides, through which the heart, liver, and digestive tract can be seen. Recent research found that some glass frogs become even more transparent while sleeping by tucking red blood cells into their liver. Their green backs help them blend with leaves by day, while they are active and vocal at night.

Diet and feeding

These tiny frogs are insectivores that hunt at night among leaves near streams. They eat small insects such as flies, crickets, and ants, as well as spiders, snatching them with a quick tongue. Their small size limits them to equally small prey.

Habitat and range

Glass frogs live in humid montane and lowland rainforests of Central and South America, almost always near clear, flowing streams. Males often guard clutches of eggs laid on leaves overhanging the water, so that hatching tadpoles drop into the stream below. They depend on clean water and dense streamside plants.

Conservation

Many glass frog species are listed as Least Concern, but they are highly sensitive to deforestation, water pollution, and the amphibian fungal disease chytridiomycosis. Because they need pristine streams, they are useful indicators of rainforest health. Some narrow-range species are threatened or poorly known.

Frequently asked questions about the Glass Frog

Why are glass frogs transparent?

Glass frogs have translucent skin on their bellies that lets you see their internal organs, including the beating heart. The transparency is thought to help them blend in and avoid detection by predators.

What do glass frogs eat?

Glass frogs are insectivores that eat small insects such as flies, crickets, and ants, along with spiders, hunting at night among streamside leaves.

Where do glass frogs live?

They live in humid rainforests of Central and South America, almost always near clear, flowing streams where they breed on overhanging leaves.

How big are glass frogs?

Glass frogs are very small, with most species measuring only about 2 to 3 cm (0.8 to 1.2 in) in body length.

Do glass frogs care for their eggs?

Yes. In many species the male guards the eggs, which are laid on leaves above a stream, keeping them moist and protected until the tadpoles hatch and drop into the water.