Top 15 Weirdest Animals in the World

#2 Glass Frog (Centrolenidae)

A small green glass frog sitting on a leaf with transparent skin on its underside. - Photo: worldswildlifewonders/Shutterstock

Facts

• Class: Amphibians
• Order: Frogs (Anura)
• Family: Glassfrogs (Centrolenidae)
• Distribution: Southern Mexico, Bolivia, Brazil, Argentina
• Habitat: Rainforests

The Glass Frog: Why is it Transparent?

Before you scroll down any further: Be careful, things are about to get a bit gross – or absolutely fascinating?! The top side of the glass frog is a normal green color. However, if you look at the creature from underneath, you won't believe your eyes: Its belly skin is completely see-through! You can observe all its internal organs at work – its liver, its intestines, and even its tiny heart beating away.

But why did nature design this frog this way? The answer is: Perfect camouflage in the jungle! When the glass frog sits on a leaf that is illuminated by the sun, its body blends in with the surroundings. Biologists refer to this as edge blur. For predators like birds, snakes, or larger amphibians, it becomes nearly invisible, as it casts no hard shadows.

With the glass frog, you can observe all its internal organs in action. - Photo: Dr. Morley Read/Shutterstock

Habitat and Lifestyle: A True Climbing Artist

The family of Glass Frogs includes over 150 species that predominantly inhabit the moist rainforests of Central and South America. They are nocturnal and spend most of their lives high up in the trees that grow along streams and rivers. Thanks to special adhesive pads on their toes, they can easily climb even slippery, wet leaves in the dense jungle.

Through his transparent belly, you can see his insides! - Photo: bennytrapp/stock.adobe.com

Are Glass Frogs Toxic to Humans?

When people think of colorful frogs in the rainforest, they often picture the highly toxic poison dart frogs. However, the Glass Frog is completely non-toxic to humans. It has no skin toxins and relies solely on its remarkable camouflage and ability to blend in with its surroundings during the day for survival in the ecosystem.

Sources:

• Imperfect transparency and camouflage in glass frogs (https://www.pnas.org)

• Table of Contents:
• 0. Introduction
• 1. Longhorn Cowfish
• 2. Glass Frog
• 3. Sawfish
• 4. Fried Egg Jellyfish
• 5. Streaked Tenrec
• 6. Red-Lipped Batfish
• 7. Saiga
• 8. Spook Fish
• 9. Clearwing Moth
• 10. Musk Deer
• 11. Dugong
• 12. Blue Ocean Slug
• 13. Giant Isopod
• 14. Leafy Seadragon
• 15. Leaf-Tailed Gecko