Some frogs lead very different lives. Frogs that live in really warm places may spend the hottest times of year staying underground to keep cool. Like all frogs, tree frogs need to keep their skin moist. They wet their skin in pools of water that form on the branches or leaves of trees. Frogs don't drink water like people do.
Frogs take in water through their skin.
In this way, frogs get oxygen from the water. One special tree frog is the glass frog of Costa Rica. This frog has see-through skin on its belly. If you look at the frog from underneath, you will be able to see its heart and other body parts. The nostrils are two little holes above the frog's mouth.