Tree frogs are fascinating creatures. One of the best known tree frogs
is the spring peeper. They are often heard but rarely seen because
they are small. The Coqui tree frog of Puerto Rico stays in
trees at night. Every morning they all leap into a "rain" of frogs.
Cuban tree frogs can grow to be five inches. That is the largest.
Tree frogs are found in most parts of the world. They spend most of their lives in shrubs. All frogs must live in wet warm regions. They need to be around moisture because oxygen is absorbed by tiny blood vessels close to the surface of their skin. Frog skin has mucous producing glands that help keep it moist. Frogs must also depend on cutaneous respiration for their oxygen supply. In this method of respiration, oxygen from the air is drawn into a frog's body by the blood vessels that lie close to the skin. Waste gas and carbon dioxide are also released the same way. In order for all the transfer to take place the frog's skin must be moist.
Croaking and chirping noises you hear near ponds usually occur on spring or summer nights. During rainy days you may see frogs hopping through grass or among the plants of a garden.
Most tree frogs are about 2 inches (5 centimeters) in length, which is small. Most tree frogs are smaller than bull frogs and green frogs. They have skinny tummies and long legs. They have wide sticky disks on their feet that help them climb up trees and branches. An important skill to tree frogs is climbing.
Different skin colors are created by changes in the pigments within a frog's skin. On bright, hot days frog's skin becomes lighter in color. On dark, cool days frog's skin may become darker, to absorb needed warmth. The skin color changes to match the animal's environment.
