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 ...

A new study from the Smithsonian Tropical Research Institute (STRI) shows that red-eyed treefrog embryos hatch early when exposed to high ammonia levels — an environmental cue that it’s too hot and ...

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 ...

An optical illusion is a visual phenomenon where the brain misinterprets what the eyes perceive, creating a false or misleading impression of reality. This occurs because the brain processes visual ...