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Tradeoffs between bite force and gape in Eulemur and Varecia.

Publication ,  Journal Article
Laird, MF; Polvadore, TA; Hirschkorn, GA; McKinney, JC; Ross, CF; Taylor, AB; Terhune, CE; Iriarte-Diaz, J
Published in: J Morphol
May 2024

In 1974, Sue Herring described the relationship between two important performance variables in the feeding system, bite force and gape. These variables are inversely related, such that, without specific muscular adaptations, most animals cannot produce high bite forces at large gapes for a given sized muscle. Despite the importance of these variables for feeding biomechanics and functional ecology, the paucity of in vivo bite force data in primates has led to bite forces largely being estimated through ex vivo methods. Here, we quantify and compare in vivo bite forces and gapes with output from simulated musculoskeletal models in two craniofacially distinct strepsirrhines: Eulemur, which has a shorter jaw and slower chewing cycle durations relative to jaw length and body mass compared to Varecia. Bite forces were collected across a range of linear gapes from 16 adult lemurs (suborder Strepsirrhini) at the Duke Lemur Center in Durham, North Carolina representing three species: Eulemur flavifrons (n = 6; 3F, 3M), Varecia variegata (n = 5; 3F, 2M), and Varecia rubra (n = 5; 5F). Maximum linear and angular gapes were significantly higher for Varecia compared to Eulemur (p = .01) but there were no significant differences in recorded maximum in vivo bite forces (p = .88). Simulated muscle models using architectural data for these taxa suggest this approach is an accurate method of estimating bite force-gape tradeoffs in addition to variables such as fiber length, fiber operating range, and gapes associated with maximum force. Our in vivo and modeling data suggest Varecia has reduced bite force capacities in favor of absolutely wider gapes compared to Eulemur in relation to their longer jaws. Importantly, our comparisons validate the simulated muscle approach for estimating bite force as a function of gape in extant and fossil primates.

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Published In

J Morphol

DOI

EISSN

1097-4687

Publication Date

May 2024

Volume

285

Issue

5

Start / End Page

e21699

Location

United States

Related Subject Headings

  • Mastication
  • Male
  • Lemur
  • Jaw
  • Female
  • Bite Force
  • Biomechanical Phenomena
  • Animals
  • Anatomy & Morphology
  • 3109 Zoology
 

Citation

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ICMJE
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Laird, M. F., Polvadore, T. A., Hirschkorn, G. A., McKinney, J. C., Ross, C. F., Taylor, A. B., … Iriarte-Diaz, J. (2024). Tradeoffs between bite force and gape in Eulemur and Varecia. J Morphol, 285(5), e21699. https://doi.org/10.1002/jmor.21699
Laird, Myra F., Taylor A. Polvadore, Gabrielle A. Hirschkorn, Julie C. McKinney, Callum F. Ross, Andrea B. Taylor, Claire E. Terhune, and Jose Iriarte-Diaz. “Tradeoffs between bite force and gape in Eulemur and Varecia.J Morphol 285, no. 5 (May 2024): e21699. https://doi.org/10.1002/jmor.21699.
Laird MF, Polvadore TA, Hirschkorn GA, McKinney JC, Ross CF, Taylor AB, et al. Tradeoffs between bite force and gape in Eulemur and Varecia. J Morphol. 2024 May;285(5):e21699.
Laird, Myra F., et al. “Tradeoffs between bite force and gape in Eulemur and Varecia.J Morphol, vol. 285, no. 5, May 2024, p. e21699. Pubmed, doi:10.1002/jmor.21699.
Laird MF, Polvadore TA, Hirschkorn GA, McKinney JC, Ross CF, Taylor AB, Terhune CE, Iriarte-Diaz J. Tradeoffs between bite force and gape in Eulemur and Varecia. J Morphol. 2024 May;285(5):e21699.
Journal cover image

Published In

J Morphol

DOI

EISSN

1097-4687

Publication Date

May 2024

Volume

285

Issue

5

Start / End Page

e21699

Location

United States

Related Subject Headings

  • Mastication
  • Male
  • Lemur
  • Jaw
  • Female
  • Bite Force
  • Biomechanical Phenomena
  • Animals
  • Anatomy & Morphology
  • 3109 Zoology