Journal of Comparative Physiology A

, Volume 203, Issue 2, pp 111–120 | Cite as

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


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.


Manatee Sirenian Tactile Hydrodynamic Vibrissae 



Follicle-sinus complex


Frequency (Hz)



We appreciate the support of Mote Marine Laboratory in providing the animals and facilities for this project. Thanks to the many volunteers from Mote Marine Laboratory and students from New College of Florida that assisted on this project. We gratefully acknowledge Guido Dehnhardt and Wolf Hanke for their expertise and equipment loan during training, as well as Ronnie and John Enander, the Thurell family, and New College Foundation. Yareli Alvarez and Madi Huffstickler provided assistance in the preparation of the manuscript. This work was conducted under US Fish and Wildlife Service Permit MA837923. It was supported by the National Science Foundation (IOS-0920022/0919975/0920117). All experimental procedures were approved by the Mote Marine Laboratory IACUC prior to implementation.


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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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