Functional consequences of tooth design: Effects of blade shape on energetics of cutting

Philip S.L. Anderson, Michael LaBarbera

Research output: Contribution to journalArticlepeer-review

Abstract

Dental structures capture, retain and fragment food for ingestion. Gnathostome dentition should be viewed in the context of the prey's material properties. Animal muscle and skin are mechanically tough materials that resist fragmentation unless energy is continually supplied directly to the tip of the fracture by some device such as a blade edge. Despite the variety of bladed tooth morphologies in gnathostomes, few studies have experimentally examined the effects of different blade designs on cutting efficiency. We tested the effects of blades with and without contained notches and in a 'fang' configuration on the force and energy required to fracture raw, unprocessed biological tissues (fish and shrimp) using a double guillotine device. Blade design strongly affects the work required to fragment biological tissues. A notched blade reduced the work to fracture of tissues tested by up to 600 Jm-2 (50% reduction). The specific angle of the notch had a significant effect, with acute angles more effectively reducing work to fracture. A bladed triangle matched to a notch reduced work to fracture more than a notch-straight blade pair. Strain patterns seen while cutting photoelastic gelatin indicate that the reduction in work to fracture with triangular and notched blades arises from a combination of 'trapping ability' and blade approach angle causing the material to fracture at lower overall strain levels. These results show that the notched blade designs found in a wide variety of vertebrate dentitions reduce the energy expenditure (and presumably handling time) when cutting tough prey materials like animal flesh.

Original languageEnglish (US)
Pages (from-to)3619-3626
Number of pages8
JournalJournal of Experimental Biology
Volume211
Issue number22
DOIs
StatePublished - Nov 15 2008
Externally publishedYes

Keywords

  • Blades
  • Cutting
  • Dentition
  • Fracture
  • Toughness

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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