Building on the shoulders of a giant: Using technology to extend biosonar research pathways first blazed by Sam H. Ridgway.

Abstract

Underwater biosonar research began in the middle of the last century by a handful of pioneers. Among the debates that raged in the scientific literature for the first 30 years were (1) the origin of biosonar signals and their formation into a transmitted beam and (2) the pathways and mechanisms for sound reception. Ridgway and his colleagues (1980) provided definitive proof for the nasal origin of sonar signals using electromyography and small pressure catheters inserted into various airways. Ridgway also collaborated on a series of experiments that attempted to discern the structure and function of the tympanoperiotic complex. My colleagues and I have combined remote imaging technology, high-speed video endoscopy, and finite element analysis to pinpoint the site of sonar signal generation, posit novel sound propagation pathways into and out of the heads of various odontocetes, and uncover new elements of the structure and function of the tympanoperiotic complex. These results will be presented in light of Ridgway’s pioneering work.