Hearing and Sound Communication in Amphibians: Prologue and Prognostication

The vertebrate class Amphibia is composed of three orders: the Gymnophiona (caecilians) or legless amphibians (not known to vocalize), the Urodela (salamanders and newts), and the Anura (frogs and toads). With few exceptions, anuran amphibians are the most highly vocal of the amphibia, although the Pacific giant salamander (Dicamptodon tenebrous) is among a small group of urodeles known to produce calls. What do these sounds mean? How are they encoded in the nervous system? In 1999, Volume 11 of the Springer Handbook of Auditory Research (SHAR) entitled: Comparative Hearing: Fish and Amphibians (Fay and Popper 1999) presented a direct comparison between the auditory systems of fish and amphibians. Why then, only seven years later, do we bother to assemble much that is known for the amphibians in a new volume? First, the topics in the present volume are all specific to amphibians and attempt to provide comprehensive coverage of current knowledge of the auditory system and its function in these fascinating animals. Second, there have been significant advances in our understanding of the physiology and behavior of anuran amphibians (the subject of most intense research) since the SHAR volume appeared. Third, in December of 2002 at the meeting of the Acoustical Society of America in Cancun, Mexico, one of us (PMN) organized a symposium highlighting the seminal work of Robert Capranica entitled: “Amphibian Bioacoustics Honoring Robert Capranica.” In addition to Bob and his wife Pat, many of his former students, friends, and his PhD mentor, Moise Goldstein, were present. The excitement of being able to put together a program that was inspired by, dedicated to, and appreciated by Bob was palpable. That symposium was the genesis of the present monograph, and we believe that the high quality of its content speaks volumes to Bob’s character, his dedication to his students, and his insistence on high-quality science by example. These qualities are reflected in the enthusiasm displayed by every contributor to this volume, their fervor for the field, their genuine desire for excellence, and their generosity of spirit.