The document discusses walrus hearing and communication. It describes how sound travels through the outer, middle and inner ear of walruses. While walruses cannot speak, they communicate through sounds, touch, smell and behavior. The document outlines a study that recorded underwater walrus sounds to analyze for ultrasonic components and potential echolocation use. Recordings were analyzed with software to identify sounds and understand their function. Though many sounds were recorded, their purpose remains unclear and most were not ultrasonic.