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The utilization of prey-simulating electrodes to analyze the predatory behavior of the great hammerhead shark (Sphyrna mokarran)

O’Connell, Craig P.
Zoology and ecology 2018 v.28 no.2 pp. 75-85
Dasyatis americana, Sphyrna mokarran, electrodes, field experimentation, foraging, predation
A new observation of a great hammerhead shark (Sphyrna mokarran) natural predation on a southern stingray (Hypanus americana) is described in combination with two novel field experiments that investigate both: (1) the sensory cues that elicit S. mokarran foraging responses, as well as (2) the unique prey handling techniques that make this hammerhead such a specialized predator. This study is the first to demonstrate the importance of electro-sensory cues at close ranges for prey detection in S. mokarran. In addition, both the observed natural predation and field experiments provided visual evidence of the repeated prey manipulation technique, termed ‘lateral headshake repositioning’, that may maximize prey handling and foraging success. Further research using more accurate chemo-sensory cues (e.g. those from southern stingrays – Hypanus americana) or varying decoy manipulations (e.g. a buried decoy with active electrodes) is warranted to enhance our understanding of the sensory allocation and prey handling behavioral patterns in relation to the foraging success of this endangered predator.