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Bite force and cranial bone strain in four species of lizards

Ross, Callum F.; Porro, Laura B.; Herrel, Anthony; Evans, Susan E.; Fagan, Michael J.


Callum F. Ross

Laura B. Porro

Anthony Herrel

Susan E. Evans

Michael J. Fagan


In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared to mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitudes. Within individuals the most consistent determinants of variance in bone strain magnitudes are gage location and bite point, with the importance of bite force varying between individuals. Inter-site variance in strain magnitudes—strain gradient—is present in all individuals, and varies with bite point. Between individuals within species, variance in strain magnitude is driven primarily by variation in bite force, not gage location or bite point, suggesting that inter-individual variation in patterns of strain magnitude is minimal. Between species, variation in strain magnitudes is significantly impacted by bite force and species membership, as well as by interactions between gage location, species, and bite point. Independent of bite force, species differences in cranial strain magnitudes may reflect selection for different cranial morphology in relation to feeding function, but what these performance criteria are is not clear. The relatively low strain magnitudes in Iguana and Uromastyx compared to other lizards may be related to their herbivorous diet. Cranial kinesis and the presence or absence of postorbital and supratemporal bars are not important determinants of inter-specific variation in strain magnitudes.


Ross, C. F., Porro, L. B., Herrel, A., Evans, S. E., & Fagan, M. J. (2018). Bite force and cranial bone strain in four species of lizards. The journal of experimental biology, 221(23), jeb.180240.

Journal Article Type Article
Acceptance Date Oct 16, 2018
Online Publication Date Oct 23, 2018
Publication Date Dec 4, 2018
Deposit Date Nov 5, 2018
Publicly Available Date Oct 24, 2019
Journal The Journal of Experimental Biology
Print ISSN 0022-0949
Electronic ISSN 1477-9145
Publisher The Company of Biologists
Peer Reviewed Peer Reviewed
Volume 221
Issue 23
Pages jeb.180240
Keywords Insect Science; Animal Science and Zoology; Aquatic Science; Physiology; Ecology, Evolution, Behavior and Systematics; Molecular Biology
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