CHAPTER 6 - The Frog

This chapter examines the anatomy of the frog. The North American bullfrog—Rana catesbeiana—is a member of Anura, which together with Caudata (sala­manders and newts) and Gymnophiona (caecilians or apodans) form Amphibia. Frogs have highly specialized locomotory features that make them instantly recognizable. Frog's body is rigid, short, and wide, the hind limbs are long and used for jumping, and the tail is absent. Anurans generally have an aquatic tadpole or larval stage and undergo metamorphosis to produce the radi­cally different adult form, but different reproductive strategies have evolved. Some, such as some members of Pipidae—a group of specialized aquatic frogs—produce eggs that develop directly into juvenile frogs, whereas other pipids have aquatic larvae. Rana catesbeiana is a native North American frog with a fairly wide natural distribution and has been introduced in parts of Asia, South America, and Europe. Bullfrogs vary considerably in size, but length tends to be between 10 and 17 cm, although many are 20 cm in length. They live in water, hence, are found near lakes, ponds, and rivers.