Behaviorally measured tactile sensitivity in the common bottlenose dolphin,Tursiops truncatus |
| |
Authors: | Madelyn G Strahan Dorian S Houser James J Finneran Jason Mulsow Daniel E Crocker |
| |
Institution: | 1. Biologic and Bioacoustic Research, National Marine Mammal Foundation, San Diego, California;2. U.S. Navy Marine Mammal Program, Naval Information Warfare Center Pacific, San Diego, California;3. Department of Biology, Sonoma State University, Rohnert Park, California |
| |
Abstract: | Little research has been conducted on the somatosensory system of toothed whales and it remains uncertain how tactile sensitivity varies about their bodies. In this study, tactile sensitivity to high-frequency (250-Hz) displacement of the skin was quantified in three trained adult common bottlenose dolphins (Tursiops truncatus) using a vibratory device (tactor). The magnitude of skin displacement was controlled by varying the voltage to the tactor held against the skin surface with a constant force. Tactile thresholds were determined using an adaptive method of limits in which dolphins reported perception of the tactile stimulus by producing a whistle. Displacement thresholds ranged from 2.4 to 40 μm, with the greatest sensitivity found along the rostrum, melon, and blowhole. Sensitivity decreased caudally along the body, with the dorsal fin and tip of the fluke being the least sensitive locations tested. The results support hypotheses that the follicles on the dolphin rostrum are particularly important for perception. The reduction in tactile sensitivity at the appendages is consistent with their primary role in stabilization and locomotion compared to exploration or environmental sensing. |
| |
Keywords: | bottlenose dolphin displacement Pacinian corpuscle skin staircase procedure tactile sensitivity |
|
|