Journal of Comparative Physiology A

, Volume 203, Issue 2, pp 111–120

Detection of hydrodynamic stimuli by the postcranial body of Florida manatees (Trichechus manatus latirostris)

  • Joseph C. GaspardIII
  • Gordon B.  Bauer
  • David A. Mann
  • Katharine Boerner
  • Laura Denum
  • Candice Frances
  • Roger L. Reep
Original Paper

DOI: 10.1007/s00359-016-1142-8

Cite this article as:
Gaspard, J.C., Bauer, G.B., Mann, D.A. et al. J Comp Physiol A (2017) 203: 111. doi:10.1007/s00359-016-1142-8

Abstract

Manatees live in shallow, frequently turbid waters. The sensory means by which they navigate in these conditions are unknown. Poor visual acuity, lack of echolocation, and modest chemosensation suggest that other modalities play an important role. Rich innervation of sensory hairs that cover the entire body and enlarged somatosensory areas of the brain suggest that tactile senses are good candidates. Previous tests of detection of underwater vibratory stimuli indicated that they use passive movement of the hairs to detect particle displacements in the vicinity of a micron or less for frequencies from 10 to 150 Hz. In the current study, hydrodynamic stimuli were created by a sinusoidally oscillating sphere that generated a dipole field at frequencies from 5 to 150 Hz. Go/no-go tests of manatee postcranial mechanoreception of hydrodynamic stimuli indicated excellent sensitivity but about an order of magnitude less than the facial region. When the vibrissae were trimmed, detection thresholds were elevated, suggesting that the vibrissae were an important means by which detection occurred. Manatees were also highly accurate in two-choice directional discrimination: greater than 90% correct at all frequencies tested. We hypothesize that manatees utilize vibrissae as a three-dimensional array to detect and localize low-frequency hydrodynamic stimuli.

Keywords

Manatee Sirenian Tactile Hydrodynamic Vibrissae 

Abbreviations

FSC

Follicle-sinus complex

F

Frequency (Hz)

Funding information

Funder NameGrant NumberFunding Note
National Science Foundation
  • IOS-0920022/0919975/0920117

Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.Science and Conservation, Pittsburgh Zoo & PPG AquariumPittsburghUSA
  2. 2.Division of Social SciencesNew College of FloridaSarasotaUSA
  3. 3.Mote Marine Laboratory and AquariumSarasotaUSA
  4. 4.Loggerhead InstrumentsSarasotaUSA
  5. 5.Department of Physiological Sciences, Aquatic Animal Health ProgramUniversity of Florida, College of Veterinary MedicineGainesvilleUSA

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