Red-eyed tree frogs use 'startle coloration' to momentarily stun predators with a flash of neon color.

The red-eyed tree frog (Agalychnis callidryas) is a master of a survival mechanism known as deimatic behavior. During the day, it remains motionless on the underside of leaves, tucking its bright limbs inward and closing its eyes to achieve near-perfect camouflage. This state of rest is essential for avoiding detection by sharp-eyed predators like tropical birds and arboreal snakes.When a predator approaches too closely, the frog utilizes 'startle coloration' as a secondary defense. By suddenly opening its bulging red eyes and revealing its vibrant blue-and-yellow striped flanks, it creates a visual overload for the attacker. This phenomenon, often studied by herpetologists, exploits the predator's sensory processing, causing a momentary hesitation or 'freeze' response.Research published in journals like 'Animal Behaviour' suggests that these high-contrast colors signal a potential threat or toxicity, even though the red-eyed tree frog is not actually poisonous. This bluff gives the frog approximately 100 to 300 milliseconds of time to leap into the safety of the dense canopy. Once it lands and tucks its limbs back in, the frog effectively 'disappears' again, leaving the predator searching for a bright object that no longer exists.