Abbreviations: CP, cribriform plate; ORG, olfactory receptor gene. Body mass estimates are species means. Where sexual dimorphism was present, we considered the sex of individuals when deriving the species body mass. Individual dog breed body size estimates were averaged to calculate the mean body mass of the dog (Canis familiaris). References for body mass and ORG data listed below the table. For cribriform plate surface area data of individual specimens, see table S5.