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. 2016 Aug 10;3(8):160141.
doi: 10.1098/rsos.160141. eCollection 2016 Aug.

Modelling tooth-prey interactions in sharks: the importance of dynamic testing

Katherine A Corn  1 , Stacy C Farina  2 , Jeffrey Brash  3 , Adam P Summers  4
Affiliations

Modelling tooth-prey interactions in sharks: the importance of dynamic testing

Katherine A Corn et al. R Soc Open Sci. .

Abstract

The shape of shark teeth varies among species, but traditional testing protocols have revealed no predictive relationship between shark tooth morphology and performance. We developed a dynamic testing device to quantify cutting performance of teeth. We mimicked head-shaking behaviour in feeding large sharks by attaching teeth to the blade of a reciprocating power saw fixed in a custom-built frame. We tested three tooth types at biologically relevant speeds and found differences in tooth cutting ability and wear. Teeth from the bluntnose sixgill (Hexanchus griseus) showed poor cutting ability compared with tiger (Galeocerdo cuvier), sandbar (Carcharhinus plumbeus) and silky (C. falciformis) sharks, but they also showed no wear with repeated use. Some shark teeth are very sharp at the expense of quickly dulling, while others are less sharp but dull more slowly. This demonstrates that dynamic testing is vital to understanding the performance of shark teeth.

Keywords: Carcharhinus; Galeocerdo cuvier; Hexanchus griseus; cutting performance; saw.

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Figures

Figure 1.
Figure 1.
Morphological diversity in shark teeth. Shark teeth exhibit a high degree of morphological variation. These line drawings of eight tooth types demonstrate diversity in tooth shape. Scale bar, 1 cm.
Figure 2.
Figure 2.
Example blades. Teeth were attached to blades using epoxy, with the lingual face against the blade. We used separate blades for teeth from the upper and lower jaw of Hexanchus griseus.
Figure 3.
Figure 3.
Sawing apparatus with fulcrum. Blades were used on a reciprocating saw mounted on a fulcrum. Depression and release of the left side of the fulcrum allowed the right side, holding the saw, to fall onto the section of salmon and through a gap in the cutting board.
Figure 4.
Figure 4.
ANOVA results from cutting tests. ANOVA revealed performance differences in cutting ability among tooth morphologies (n = 3 for each species; d.f. = 2, 6; p < 0.01). Post hoc testing showed that Hexanchus griseus teeth had lower cutting ability than the Galeocerdo cuvier and Carcharhinus tooth types.
Figure 5.
Figure 5.
Successive testing results. Repeated use of a single blade over 17–19 trials resulted in a general pattern of decreased cutting ability in Galeocerdo cuvier and Carcharhinus falciformis.
See this image and copyright information in PMC

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