Frogs and Toads
Your Happy Healthy Pet
Chapter One
What Are Frogs
and Toads?
Frogs and toads are four-legged, tailless, air-breathing vertebrates that represent
the link between the fish and reptiles and all other air-breathing
species, including humans. They are members of a class or group of vertebrates
known as the Amphibia, a word that means "dual life" and refers to the fact that
amphibian life occurs in two phases-one in the water and the other on land. It
also alludes to the fact that many amphibians are, well, amphibious, and are as
fully at home in the water as they are on land (although there are many notable
exceptions, including species that never leave the water and others that stay on
land or in trees and never enter the water at all).
The first amphibians, the labryinthodonts, took the great leap from water to
land during the Devonian period some 400 million years ago. However, fossils
of frogs appear much later, in the Jurassic period of North America, some 280
million years ago.
The other amphibian groups or orders include the Caudates or Ur ... read full excerpt from Frogs and Toads: Your Happy Healthy Pet ebook
