Vision, Audition, and Chemoreception in Dolphins and Other Marine Mammals
Paul E. Nachtigall
Naval Ocean Systems Center,
Marine mammal brains are active vital centers for the perception and interpretation of environmental information received through a variety of sensory modalities. While it may be difficult to directly examine the question of animal consciousness or self-awareness ( Griffin, 1983) quantifiable objective techniques exist for examining the abilities of animals to perceive their environments. Most definitions of consciousness include a statement of awareness to sensations and most definitions of "cognitive processes" include sensation and perception ( Mayer, 1983). The techniques of animal psychophysics allow an examination of sensation through the interpretation of an animal's behavior. Carefully interpreted experimental designs and psychophysical procedures have allowed us a fascinating view of the sensory processes, and thus the perceptual world, of dolphins and other marine mammals.
To optimize feeding, reproduction, and predator avoidance the sensory systems of animals must accurately gather available information. Rich sources of sound, light, and chemical stimuli fill the marine environment. Neurophysiological and psychophysical research with marine mammals has primarily concentrated on the study of audition and vision but taste reception experiments have recently been done. An examination of the sensory capabilities of a number of marine mammal species provides a comparative perspective to the variety of solutions to common problems that dolphins and other marine mammals encountered when returning to an aquatic environment.