Amphibians first appeared on Earth around 360 million years ago. For tens of millions of years, they were the dominant land animals on Earth. Some of these ancient creatures were very big, and they terrorized smaller animals. Amphibians evolved from fishes that had fins that looked like legs. These fish may have crawled on to the land to escape their enemies, and also because they were attracted by the good supply of food on land.
Gradually, these first amphibians developed lungs for breathing, and their fins developed into limbs for crawling. Over hundreds of millions of years, many different amphibians evolved and disappeared, leaving the familiar salamanders and frog of today.
