Once heard, the “coda” song of the male walrus is one of those unforgettable sounds in the world. It is comprised of two basic types of elements, series of evenly-delivered taps followed by an extraordinary bell or gong-like sound. The ringing quality of this latter element is astonishing, especially in an aquatic environment, and that such a sound is produced by a walrus seems all the more improbable (but true). The function is not fully understood, but may convey dominance status to potential mates and rivals.
(Several recordings of bird and animal sounds – audio and video – are available at http://macaulaylibrary.org/.
Walrus is from http://macaulaylibrary.org/staff-picks. )