Saint Nicholas is said to have a twinkle in his eye, but there's a real health condition that creates a similar effect in ...

Red-eyed tree frog. Photo by Rhett Butler. In recognition of Amphibian Ark winning mongabay.com’s 2011 conservation award, our pictures of the day this week will focus on amphibians. The red-eyed tree ...

The red-eyed tree frog has become one of Costa Rica’s most iconic creatures, admired for its vibrant colors and widespread presence across the country. This frog, known for its striking red eyes, ...

Red-eyed tree frog. Photo by Rhett Butler (2011). The red-eyed tree frog (Agalychnis callidryas) is one of the most colorful and best-known tree frogs (it is often used in advertisements). The ...

Female red-eyed tree frogs are more than twice as likely to select a mate if they can feel the vibrations of their call instead of only hearing it. These small, bright-green frogs (Agalychnis ...