Bite force sexual dimorphism in Canidae (Mammalia: Carnivora): relations between diet, sociality and bite force intersexual differences
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Laboratório de Mastozoologia, Departamento de Zoologia, Centro de Biociências, Universidade Federal de Pernambuco
Laboratório de Síntese Ecológica e Conservação da Biodiversidade - ECOFUN, Universidade Federal Rural de Pernambuco
Diego Astúa   

Universidade Federal de Pernambuco
Online publication date: 2020-09-03
Publication date: 2020-09-03
Hystrix It. J. Mamm. 2020;31(2):0
Bite force is a key trait for understanding aspects of vertebrate ecology and evolution, as it relates directly to different evolutionary pressures, like diet and behaviour. Sexual dimorphism in bite force (SDBF) is an underexplored condition that may shed light on niche divergence between sexes and the effects of sexual selection in species. Here we evaluated differences in modelled bite forces between sexes within Canidae (33 species and two subspecies) and assessed their possible correlations with diet, sociality, hunting strategies, and size dimorphism. We calculated SDBF and bite force quotients through indexes and compared them among different diets, hunting strategies, and sociality groups. Furthermore, we correlated the indexes and size sexual dimorphism using phylogenetic independent contrasts. Only two species showed significant SDBF: the Cape fox (Vulpes chama) and the Ethiopian wolf (Canis simensis). We found no significant differences in bite force dimorphism intensity between sociality levels, dietary levels, or hunting strategies. We found a relationship between bite force sexual dimorphism and size sexual dimorphism, and a correlation between bite force and the bite force quotient dimorphism. However, we found no association between sexual dimorphism in bite force quotient and sexual size dimorphism. Our findings show that Canidae do not have bite force dimorphism, possibly due to the widespread social monogamy in the family, when compared to other Carnivora. This implies possible restrictions that constraint the range of bite strength in adults, especially in females.
We are thankful to the following curators and/or collection managers for access to the specimens used in this study under their care, help during our visits or loans: Robert Voss, Teresa Pacheco, John Flynn and Judy Galkin (AMNH); Bruce Patterson (FMNH) and Robert Fisher (USNM). We are thankful to Erika Hingst-Zaher, for her collaboration in the earlier studies that resulted in this dataset, to Alessandra Lamarca and Carlos Schrago for providing us the files with their phylogenetic tree, and to an anonymous reviewer for suggestions that improved our manuscript. This work was developed while ARM received an undergraduate fellowship from FACEPE. ARM is now supported by a doctoral fellowship from CAPES. EMD was supported by fellowships from FACEPE and CNPq, and DA is or was supported by grants from CNPq, CAPES, FACEPE, and FAPESP for the acquisition of equipment used for data collection and during its development.