An analysis of sexual size dimorphism in goose

1. Sexual size dimorphism (SSD) is a common phenomenon in animals. Rensch’s rule states that larger species generally exhibit a higher male to female body size ratio than smaller ones.2. Domesticated animals offer excellent opportunities for testing predictions of the functional explanations of Rensch’s rule and this was tested in a meta-analysis of SSD in 38 breeds of domestic geese compared among themselves and with their wild relatives (subfamily Anserinae, 35 species).3. Domestic geese and wild <i>Anser</i> species taken together supported Rench’s rule but the wild species did not.4. The non-targeted sex selection hypothesis seems to provide the best intuitive explanation for the lack of SSD in geese.