Hydrodynamic Trail-Following in Harbor Seals (Phoca vitulina)

  title={Hydrodynamic Trail-Following in Harbor Seals (Phoca vitulina)},
  author={Guido Dehnhardt and Björn Mauck and Wolf Hanke and Horst Bleckmann},
  pages={102 - 104}
Marine mammals often forage in dark or turbid waters. Whereas dolphins use echolocation under such conditions, pinnipeds apparently lack this sensory ability. For seals hunting in the dark, one source of sensory information may consist of fish-generated water movements, which seals can detect with their highly sensitive whiskers. Water movements in the wake of fishes persist for several minutes. Here we show that blindfolded seals can use their whiskers to detect and accurately follow… 
Hydrodynamic Perception in Seals and Sea Lions
In the course of pinniped evolution at least two types of whiskers evolved that realized different mechanisms for the reception of external hydrodynamic information.
Tracking of biogenic hydrodynamic trails in harbour seals (Phoca vitulina)
A harbour seal was trained to swim predefined courses, thus generating biogenic hydrodynamic trails, which were measured using Particle Image Velocimetry and showed search patterns either mostly congruent with the trail or crossing the trail repeatedly in an undulatory way.
Hydrodynamic reception in the Australian water rat, Hydromys chrysogaster
It is shown that Hydromys can detect water motions with its whiskers, and no responses to surface waves generated by a vibrating rod and resembling the surface waves caused by struggling insects were found.
Hydrodynamic Perception in Pinnipeds
The vibrissal system of pinnipeds such as harbor seals or California sea lions serves not only for the detection and identification of objects by direct touch, but also detect and analyze water movements (hydrodynamic stimuli), which can be explained by fluid-structure interactions.
Hydrodynamic trail following in a California sea lion (Zalophus californianus)
The results of this study are consistent with the hypothesis that structural differences in the vibrissal hair types of otariid compared to phocid pinnipeds lead to different sensitivity of the vibrISSae during forward swimming, but still reveal a good performance even in the species with non-specialized hair type.
Harbor seal vibrissa morphology suppresses vortex-induced vibrations
Using force measurements, flow measurements and numerical simulations, it is found that the dynamic forces on harbor seal whiskers are, by at least an order of magnitude, lower than those on sea lion whiskers, which do not share the undulated structure.
Hydrodynamic sensory threshold in harbour seals (Phoca vitulina) for artificial flatfish breathing currents
This study is the first to assess a sensory threshold of the vibrissal system for a moving harbour seal under near-natural conditions and was defined for a natural type of stimulus differing from classical dipole stimuli which have been widely used in threshold determination so far.
Hydrodynamic detection and localization of artificial flatfish breathing currents by harbour seals (Phoca vitulina)
By creating near-natural conditions, this study shows that harbour seals have the ability to detect a so-far overlooked type of stimulus, as fish emit water currents through their gill openings, providing a source of sensory information for seals in the detection of prey fish.
Are Vibrissae Viable Sensory Structures for Prey Capture in Northern Elephant Seals, Mirounga angustirostris?
To test the hypothesis that northern elephant seals have increased innervation as other pinnipeds, vibrissae from the ventral‐caudal mystacial field from nine individuals were sectioned and stained for microstructure (trichrome) and innervation (Bodian silver stain) and the results add to the growing body of evidence that phocids, and perhaps all pinnIPeds, possess highly sensitive mystacial vibrISSae that detect prey.
Foraging tactics of Baikal seals differ between day and night
Some pinniped species appear to forage during both daylight and darkness. To deter- mine any differences in the foraging tactics between day and night, we attached data loggers with a newly developed


Seal whiskers detect water movements
How do pinnipeds orientate themselves under water? As most pinniped species feed in conditions under which visibility is drastically reduced, for example at night, at great depths or in murky waters,
Hunting behavior of a marine mammal beneath the antarctic fast Ice
The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder to highlight the broad range of insights possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.
It is concluded that elephant seals are sufficiently adapted to rely on vision underwater, even while diving to depths in excess of 1000 meters where bioluminescence may be the sole source of ambient light.
The ageing of the low-frequency water disturbances caused by swimming goldfish and its possible relevance to prey detection.
Measurements in a man-made open-air pond showed that water velocities in a quasi-natural still water environment can be as small as 1 mm s(-)(1) as long as no moving animal was present in the measuring plane.
Following the invisible trail: kinematic analysis of mate-tracking in the copepod Temora longicornis.
  • M. Weissburg, M. Doall, J. Yen
  • Environmental Science
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1998
The kinematic analysis indicates both sequential and simultaneous taxis mechanisms are used by Temora to follow the odour signal, and copepods appear to use mechanisms that are similar to those employed by trail-following terrestrial insects such as ants.
Fish foot prints: morphology and energetics of the wake behind a continuously swimming mullet (Chelon labrosus Risso).
The structure of the wake behind a continuously swimming mullet was analysed qualitatively and quantitatively by applying two-dimensional particle image velocimetry to derive a kinematic explanation of the flow pattern as well as an estimate of the relative contributions of the body and the tail to thrust production.
Particle-Imaging Techniques for Experimental Fluid Mechanics
An important achievement of modern experimental fluid mechanics is the invention and development of techniques for the measurement of whole, instantaneous fields of scalars and vectors. These
The Sonar of Dolphins
  • W. Au
  • Physics
    Springer New York
  • 1993
The receiver system Characteristics of the Receiver for Simple Signals and the transmission system characteristics of the receiver for Complex Signals are compared to those of the sonar system.