Marine biologist Colleen Reichmuth says that few mammals can match the vocal talents of the walrus.Produced by David Levin. Original interview by Doug Hamilton. Learn more at pbs.org/novaNOVA 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, the Lockheed Martin Corporation, and PBS viewers.