Tree frogs are a diverse family of amphibians that includes over 800 species. Not all tree frogs live in trees. Rather, the feature that unites them has to do with their feet—the last bone in their toes (called the terminal phalanx) is shaped like a claw. Tree frogs also have toe pads to help them climb and many have extra skeletal structures in their toes. Tree frogs come in a variety of colors. Most of the U.S. species are green, gray, or brown. Some of them, like the squirrel tree frog (Hyla squirella) shown here, are chameleon-like in their ability to change color.