NOVA Minutes are a regular radio features that air three times per week on 89.7 WGBH-FM in Boston. In this episode, marine biologist Colleen Reichmuth describes the many ways a walrus can communicate using sound. Produced by David Levin. Original interview by Doug Hamilton. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. Learn more at pbs.org/nova.