Because they obtain heat from their environment, herps cannot survive in very cold regions sich as the Artic. The greatest number of species occurs in the tropical regions of the world. Amphibian skin is moist and easily dried out. It has no protective covering such as scales, feathers or fur. Since drying out would mean death, amphibians must remain in or near water, or in moist locations such as under logs or leaves.
Amphibian eggs are soft and jelly-like and like the amphibians themselves, dry out easily.
They must be laid in water or at least in a wet, protected location. Even amphibians such as toads and salamanders, which have gotten some degree of independence from water, are forced to return to water to reproduce. Amphibian young show most clearly the dependence of this group on water. The eggs hatch not into small copies of the parents but into creatures that look more like fish. These are larvae, often called tadpoles.