Red-Eyed Tree Frog
|RED-EYED TREE FROG (Agalychnis callidryas)
Tree frogs are well-known symbols of the rainforest – they have even become iconic of the need to save the rainforest habitat from destruction. Red-eyed tree frogs, with their bright eyes, feet, and side markings are a colourful reminder of how beautiful and strange wild creatures can be, and that these treasures should be protected.
Red-Eyed Tree Frogs live in the neotropical forests of Central America, as well as the southern regions of Mexico and the northern regions of South America. Although they are relatively abundant in this habitat, the increasing rate of habitat destruction makes their future stability unsure. Rainforests are being destroyed to increase the land available for farming and building cities; the trees are being cut and sold as lumber.
Perhaps best known for their eyes – red-eyed tree frogs, like other frogs in the Hylidae family have three eyelids – one that comes down, one that goes up and a third, thinner membrane that is the same shade as their eyes. This “nictitating” membrane protects the frogs sensitive eyes while allowing some vision right through it.
Their eyes, along with their other vivid coloration, are vital to their survival. Using a strategy called “startle coloration” or “flash colors”, Red-Eyed Tree Frogs surprise their predators with an overload of visual stimulation. In that moment of confusion, when their predator hesitates, the frog makes its escape, leaving behind a “ghost image” of themselves, as their predators’ eyes adjust to the bright colors they’ve just seen. That “ghost image” gives the frogs an extra second or two to vanish safely into the rainforest.
This strategy is unlike the “warning colors” that some creatures use to warn their predators that they are toxic. The neon sea slug and monarch butterfly, for example, are brightly colored – but for a different reason. Their predators have learned that eating something bright could lead to a stomach ache or worse, even death. Red-eyed tree frogs are not poisonous – they have just adapted a new way to use colors to avoid being eaten.
Red-Eyed Tree Frogs are nocturnal and carnivorous. When they are not roaming the trees at night, looking for insects, moths and any other animal-prey they can catch with their fast, sticky tongues, they tuck their colors underneath their bodies, close their flashy eyes and sleep away the day. With the help of their suction-cup padded toes, they actually sleep on the underside of leaves, hanging above the forest floor. In this position, their bright green bodies are perfectly camouflaged against the leaves.
Although all amphibians spend part of their life cycle in the water, as soon as Red-Eyed Tree Frogs reach their adult stage, they rarely come down from the trees. They even lay their eggs on the underside of leaves, attaching them there with a sticky egg case filled with water. As they hatch, the tadpoles burst through the egg case and fall into the water below them, where they mature and climb right back up into the trees as soon as they can. Young froglets (at least the ones from Panama) can change color from green during the day to reddish-brown at night and have yellow eyes. Some adults can change color to darker green or reddish brown, as well.
Even with their amazing “flash” ability, Red-Eyed Tree Frogs often fall prey to larger animals, such as bats, snakes and birds. Frogs are called an “indicator species” because they tell or “indicate” the health of an ecosystem. They require very specific environmental and climatic conditions in order to carry out their life cycles. If frogs are absent or declining in an ecosystem which once supported them, it tells us that that ecosystem is probably unhealthy.