Red-eyed Tree Frog (Agalychnis callidryas)

The Red-eyed Tree Frog (Agalychnis callidryas) is one of Costa Rica’s most iconic amphibians, known for its vivid coloration and dramatic appearance. Its bright red eyes, neon-green body, and striking blue and yellow flanks make it one of the most photographed and recognized frogs in the tropical world. Despite its bold look, the frog relies on camouflage to avoid predators, spending the day motionless with its eyes closed and limbs tucked in, blending in perfectly with the surrounding leaves.

These frogs are primarily found in lowland rainforests on both the Caribbean and Pacific slopes of Costa Rica, where humidity remains high and dense foliage provides the cover and moisture they need. They're nocturnal and arboreal, meaning they spend most of their lives in trees, becoming active only at night to hunt insects and other small prey. Their adhesive toe pads allow them to cling to leaves and branches effortlessly, even in heavy rain.

One of the Red-eyed Tree Frog’s most fascinating behaviors is its “startle coloration” defense mechanism. When threatened, it suddenly opens its bulging red eyes and reveals its bright sides and legs, potentially startling predators long enough for a quick escape. During the breeding season, males call from leaves near ponds or slow-moving water, and females lay their eggs on leaves that hang over the water’s edge. When the tadpoles hatch, they drop into the water below to begin the next stage of their development.

Though not currently endangered, the Red-eyed Tree Frog faces threats from habitat loss and the global decline of amphibians due to disease and climate change. Still, in Costa Rica—where conservation efforts have protected large areas of rainforest—they remain relatively common and continue to capture the imagination of scientists, photographers, and nature lovers from around the world.