The Journal of the Marine Acoustics Society of Japan (2010)


The harbor porpoise, and other toothed whales, use a biosonar click sequence that resembles the sequence of cries used by insectivorous bats when hunting for and capturing prey. The temporal sequence starts with low rate high amplitude “searching” signals. When the porpoise detects the prey the interval between clicks becomes fairly constant in the initial part of the “approach” phase. The click intervals shorten progressively in the terminal part of the “approach”, ending in a high rate “buzz” during prey capture. The buzz clicks can continue even after capturing the prey. The duration of the approach phase varies considerably and can be quite short in beaked whales and other deep diving toothed whales. As in bats, the duration of the buzz varies depending on how rapidly the prey is captured. The use of acoustic and behavioral tags attached to several species of wild toothed whales, including the harbor porpoise, has greatly advanced our knowledge of events happening during prey capture. And the echoes from prey give an even fuller picture. The use of acoustic and behavioral tags will continue to broaden our understanding of how toothed whales use sound and echolocation in their daily life.