Green-eyed tree frog
Frogs are born with legs that are good for hopping and special pads on their toes to help them climb. In comparison, toads have shorter legs, drier skin, and are less likely to live near water. Most frogs and toads are responsible for controlling the Earth's insect population, since their diet consists mostly of insects and spiders. However, the green eyed-tree frog is also a carnivore. As a tadpole, the frogs mostly consume algae and plants. Frogs have a moist and permeable skin layer covered with mucous glands, which enables them to breathe through their skin, not just their lungs. The layer of mucus that covers them also acts as a shield, protecting them from scratches. The reason frogs have large and protruding eyes is to make up for their lack of a neck. This eye feature allows them to see everything around them. The color scheme of the green-eyed tree frog is to camouflage them from predators. Frogs with bright colors are alerting predators of their poisonous nature.
Frog
Camouflage is a common defensive mechanism in frogs. Most camouflaged frogs are nocturnal; during the day, they seek out a position where they can blend into the background and remain undetected. Some frogs have the , but this is usually restricted to a small range of colours. For example, White's tree frog ("Litoria caerulea") varies between pale green and dull brown according to the temperature, and the Pacific tree frog ("Pseudacris regilla") has green and brown morphs, plain or spotted, and changes colour depending on the time of year and general background colour. Features such as warts and skin folds are usually on ground-dwelling frogs, for whom smooth skin would not provide such effective camouflage. Certain frogs change colour between night and day, as light and moisture stimulate the pigment cells and cause them to expand or contract.
The skin of a frog is permeable to oxygen and carbon dioxide, as well as to water. There are blood vessels near the surface of the skin and when a frog is underwater, oxygen diffuses directly into the blood. When not submerged, a frog breathes by a process known as buccal pumping. Its lungs are similar to those of humans, but the chest muscles are not involved in respiration, and no ribs or diaphragm exist to help move air in and out. Instead, it puffs out its throat and draws air in through the nostrils, which in many species can then be closed by valves. When the floor of the mouth is compressed, air is forced into the lungs. The fully aquatic Bornean flat-headed frog ("Barbourula kalimantanensis") is the first frog known to lack lungs entirely.