Boiga_groove.jpg (4947 bytes)     Left, maxillary teeth of the brown tree snake, Boiga irregularis penetrating the integument of a young rodent. Note groove in the one (right), non-grooved tooth (left).

The morphology of snake teeth is correlated with the physical properties of prey skin and the mechanical processes in which the teeth participate during prey capture and swallowing. First we examine the mechanical problems teeth encounter during piercing and cutting. Second we correlate features of snake teeth with these mechanical demands. Most prey skin is a feltwork of collagen that acts like a compliant elastomer that yields when stressed. A comparison of shapes indicates that sharp, slender objects serve best to penetrate and enter such elastomers, not by use of frictional forces but instead by concentration of `forces. Similarly, blade-like edges take advantage of force concentrations, not friction, to produce damaging tensile and shear forces within the collagen feltwork when cutting skin. Delivery of oral secretions is best served by enclosed channels protecting flow of fluid. Analysis of second moments of area indicate that grooves in teeth actually weaken the bending strength of the tooth. The implications the design of snake teeth are several. Piercing and entry of compliant prey is served by sharp, slender teeth oriented with tips coincident with the angle of approach to the skin. Raised enamel ridges on tooth tips facilitate entry. Extended ridges along snake teeth contribute to effective cutting, and such blade-like teeth are usually placed at the most advantages geometric position (posterior maxillary bone) to be deployed during swallowing. Grooves in teeth do not increase bending strength and, being open, expose fluid flow to interruption by the surface of the prey. Grooved and furrowed teeth are hypothesized to facilitate fluid flow to the surface of the prey and/or to change the frictional properties of the tooth surface.

See: Kardong, K. V. and B. A. Young. 1999. Tooth structure in snakes: mechanical and functional significance.

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