title: Wide faces or large canines? The attractive versus the aggressive primate.
abstract: Hominids display marked body size dimorphism, suggestive of strong sexual selection, yet they lack significant sex differences in canine size that are commonly associated with intrasexual competition in primates. We resolve this paradox by examining sex differences in hominoid facial morphology. We show that chimpanzees, but not gorillas, exhibit clear sexual dimorphism in face width, over and above that expected based on sex differences in body size. We show that this facial dimorphism, expressed as an index, is negatively correlated with canine dimorphism among anthropoid primates. Our findings suggest that a lack of canine dimorphism in anthropoids is not owing to weak sexual selection, but rather is associated with strong sexual selection for broader face width. Enlarged cheek-bones are linked with attractiveness in humans, and we propose that the evolution of a broad face and loss of large canines in hominid males results from mate choice.
authors.affiliation: Department of Paleoanthropology, Research Institute Senckenberg, Senckenberganlage 25, 60325 Frankfurt am Main, Germany. eleanor.weston@senckenberg.de
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Weston
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Friday
authors.forename: Rufus A
authors.initials: RA
authors.lastname: Johnstone
authors.forename: Friedemann
authors.initials: F
authors.lastname: Schrenk
mesh_terms: D000818:Animals; D000886:Anthropometry; D003481:Cuspid / Q000033:anatomy & histology*; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006071:Gorilla gorilla / Q000033:anatomy & histology*; D008297:Male; D009811:Odontometry; D002679:Pan troglodytes / Q000033:anatomy & histology*; D012641:Selection, Genetic; D012727:Sex Characteristics; D012737:Sex Factors