Red-eyed tree frog

The Red-eyed tree frog is a species of New world tree frogs (Agalychnis callidryas) belonging to the taxonomic family Hylidae. There are about seven hundred different species, which are best known for their vibrant green color, and bulging red eyes.  They are also known as Red-eyed leaf frogs.

Anatomy


The Red-eyed tree frogs are known for their large, piercing red eyes. Some think that their eyes might be used as a defensive strategy called startle coloration. They have a transparent lid that covers their eyes while the frog is sleeping. When they are startled or frightened they immediately open and flash their huge red eyes. Their skin colors can vary from neon-green, blue, and even yellow. The side, of their bodies are a light bluish color, and colors from cream to yellow are striped on top of the blue. Their front two legs tend to be a bright bluish color while their feet can either be a bright orange or red. This frog's sharpest sense is sight because they have parabolic vision.

Agalychnis callidryas have specially designed, large suction-cupped toes that permit the frog to attach themselves onto almost anything they need, such as: the underside of leaves, tree trunks, and just about any types of leaves. During the day, these frogs rest on the underside of leaves, but are only able to do this because of their suction-cupped toes. The skin on their stomachs is much softer then it is on the sides or back of the frog. 

This species of tree frogs are medium sized. The female can grow to be 3.5 inches in length while the male can only grow to be around 3 inches (7 cm.) in length. They have extremely slender bodies and long lanky legs used for jumping. 

Reproduction


These frogs often reproduce in the wet and rainy season. Their mating all starts with simple croaking, most likely in unison, from the male and follows with simple instinctive formalities. In most cases, the males will all compete for the same branch. They are required to wrestle until one falls. The frogs go through a process called amplexus. This type of reproduction is typical for different frog species. This process is when the male frog, who is smaller than the female, will latch himself onto her when all of her eggs are mature; then he inseminates the eggs as they come out of the female. Amplexus can go on for more than a day.

Reproduction occurs on the underside of leaves. Since the female has the male on top of her, she must hold onto the underside of the leaf, using her suction-cupped toes, in order not to fall off. The group of eggs that the female produces is called a clutch.Immediately after the female lays her clutch, she must go fill her bladder with water, with the male still on her back. The female must fill her bladder with water between clutches in order to save her eggs. If the female fails to do this, then her eggs will simply dry up and die. Occasionally when the female goes into the water with the male still on her back, other male frogs will attempt to push him off. If the male is pushed off then the male who pushed him off will get on the female and they will create a new clutch of eggs.

After the clutch has been created and laid, it takes around five days for the tadpoles to come out and swim down to the water beneath them. After the tadpole is below the surface of the water, they begin the metamorphosis process. The metamorphosis process can take about 75-80 days for the tadpole to fully develop into a frog. 

Ecology


These frogs can be found within the treetops of South America specifically located in the different neo-tropical rainforests. These frogs live in mostly tropical rain forests, lowland forests, and surrounding hills. These places will normally be near some kind of water source. They live in temperatures that are 75F - 90F in the summer, with 60 - 100% humidity. Although in the winter, they live in temperatures that are 65F - 75F. During the winter, the rains are increased. Their habitat that they live in is mostly warm all year round. The Agalchnis callidrays are distinctly arboreal, which means tree dwelling. Red-eyed tree frogs are also spectacular jumpers and are able to jump from tree to tree. They are also 100 percent nocturnal. 

The places that these frogs live in are filled with predators. Different animals such as snakes, birds, small mammals, insects, and lizards, are all potential predators. Because these frogs do not have any toxic poisons to protect them, they depend most of the time on camouflage. Since these frogs are nocturnal, during the day they sleep on the undersides of mostly green leaves. They stay on green leaves to blend in with the environment. While the frogs are just resting, they bring in their rear limbs to cover up their loud and festive-colored sides. Then they cover their eyes with their transparent lid. By the time their sides and eyes are covered, the frogs look almost completely green. These frogs try to use startle coloration as much as they can when face to face with predators. All they need to do is flash their bulging red eyes at the predator and escape as fast as they can. When they flash their eyes, it leaves almost a "ghostly figure", in their predators eyes. It's almost as if they were staring into the sun or a light for too long. Although these frogs have different defensive methods and mechanisms, these can only go so far. This species of frog is hunted consistently by many animals. 
 * Predators

This species of frog is extremely carnivorous. To satisfy their hunger, these frogs will eat almost anything that will fit in their mouths. They might even eat other frogs that are of smaller size. These frogs devour a large amount of insects in their habitat. They eat insects such as moths, flies, beetles, and crickets. They eat small-sized invertebrates. Since many of these frogs are nocturnal, the frogs only hunt and eat at night. The younger and smaller frogs eat tinier things including fruit flies, flour beetles, and pinhead crickets. 
 * Diet

Vibrations cause early hatching?
An article found in ScienceDaily talks about how Agalchynis callidryas eggs are capable of hatching early when feeling threatened or disturbed. It gives an example: there is an egg clutch that is hanging onto the bottom of a leaf above the surface of water. Nearby, a parrot snake has been spotted, who also sees the frog clutch. The snake makes its way over to the clutch and takes a bite, collecting a few of the eggs. Because of that bite, the embryos start to move around desperately. They see the snake going in for another bite and frantically burst out of their egg coverings and drop themselves into the water. Now tadpoles, they swim away, knowing they are safe from the predator. There was question on how the embryos knew the difference between the vibrations of rain and the vibrations of a predator attempting to take a bite out of their clutch. A Boston University professor, Karen Warkentin, found that according to her research, it is a particular characteristic of the vibrations that are able to shake the clutch and to signal the embryos to make their move. Several details of the vibrations are: the speed of the vibrations, how hard or light the clutch of eggs is jerked, and also the amount of time between the vibrations and the movements that inform the embryos when to come out.

It normally takes around six to eight days for the embryo to officially hatch, but if the embryo is being attacked it is able to hatch thirty percent faster than normal to escape to safety. Warkentin did more studies and observations and came to find that the embryos react to the predator's vibrations rather than vibrations from the weather. In the end, she discovered that the embryo had moved after the snake had bitten into the clutch and not before. In conclusion, she found that even embryos have wonderful perception to danger and their warning vibrations.