Sexual-size dimorphism in two synanthropic rat species: Comparison and eco-evolutionary perspectives

Sexual dimorphism is a common trait in many mammal species and sexual-size dimorphism (SSD) repre-sents its commonest form. Rattus rattus and Rattus norvegicus are two cosmopolitan, polygynous species, for which a male-biased SSD has been anecdotally reported, but never quantified. In this work, we assessed the occurrence of SSD in both species and we tested the hypothesis that R. norvegicus has a more evident SSD than R. rattus, in agreement...