Potential for sound sensitivity in cephalopods.

Hearing is a primary sense in many marine animals, and we now have a reasonable understanding of what stimuli generate clear responses, the frequency range of sensitivity, expected threshold values, and mechanisms of sound detection for several species of marine mammals and fishes ( Au et al. 2000 ; Fay 1988 ) . For marine invertebrates, our knowledge of hearing capabilities is relatively poor and a definition or even certainty of sound detection is not agreed on (Webster et al. 1992 ) despite their magnitude of biomass and often central role in ocean ecosystems. Cephalopods (squid, cuttlefish, octopods, and nautilus) are particularly interesting subjects for invertebrate sound detection investigations for several reasons. Ecologically, they occupy many of the same niches as sound-sensitive fish (Budelmann 1994 ) and may benefit from sound perception and use for the same reasons, such as to detect predators, navigate, or locate conspecifics. Potential for Sound Sensitivity in Cephalopods