Phylogenetic Tree (IMAGE) University of California - Santa Cruz Caption A portion of the phylogenetic tree of the squirrel family (Sciuridae) illustrates how promiscuous ancestral species (black dots) gave rise to both monogamous species (blue dots) and polygynous species (red dots). Marmots (genus Marmota), for example, are mostly monogamous, although there are a couple of polygynous species. Ground squirrels in the genus Spermophilus include promiscuous, polygynous, and monogamous species. Credit Sinervo et al., American Naturalist, 2019 Usage Restrictions For use only with news coverage of this research License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.