Huge dinosaurs roamed the swamps and reptiles of many kinds swam in the sea or even flew. This was a time known as The Jurassic Period . The earliest known frog appeared during the Jurassic period, about 260 million years ago .
Scientists believe that the oldest frogs developed jumping legs to avoid being eaten by dinosaurs.
Fossils show that the skeletal shape and body plan of the frog has remained almost unchanged. Amphibians have survived through the age of dinosaurs and hung on through the mass extinction during which the dinosaurs perished.