Amphibia  

          This class belongs to tetrapodes (with 4 limbs). Frogs and Bufo are the best examples of this class. Their name denotes that they spend a period of their life cycle in water in which gills are used for respiration and tails for swimming, where the other part of life is spent on earth where lungs are used for respiration. The difference between frogs and Bufo is that frogs have thin skin that can lose water easily whereas Toads have thick skin provided with nodules and they have and ability to tolerate drought. Frogs and Bufo are characterized by their ability to change color as a means of disappearance. Frogs and Bufo are found in the eastern region of Saudi Arabia especially Al-Hassa and Kateef in the water collection at mountain apes, and at the extension of the wastern shore of the Kingdom.