Committee Chair

Hayes, Loren

Committee Member

Klug, Hope; Schorr, Mark


Dept. of Biological and Environmental Sciences


College of Arts and Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


Recent debate has focused on how ecology shapes the evolution of group-living and cooperation in social vertebrates. Evidence suggests that group-living and cooperation enhance reproductive success under harsh local conditions in some species. Across two years, I studied two populations of Octodon degus, a plurally breeding rodent, to answer three questions: (1) Does living in large groups and having strong social network strength improve access to resources in harsh environments? (2) Does increased access to resources improve the reproductive success of group-living females? (3) Does living in large groups and having strong social network strength improve reproductive success of females in harsh environments? I quantified group sizes and social network strength, ecological conditions at burrow systems, and per capita offspring weaned of social groups to answer these questions. I found site- and year-specific relationships in partial support of predictions, demonstrating habitat-specific costs and benefits of social group-living and cooperation.


I would like to thank my dedicated advisor, Dr. Loren Hayes, for his continued guidance, wisdom and support during my many years in the Hayes lab. I also thank my thesis committee members, Dr. Hope Klug and Dr. Mark Schorr, for their advice in statistical analyses and the writing process. I am extremely thankful for, and indebted to my collaborators in Chile. Firstly, I thank Dr. Luis Ebensperger and his lab members at Pontificia Universidad Católica de Chile, without whom this project would not exist. Secondly, I thank Dr. Rodrigo Vasquez and his lab members at Universidad de Chile for providing me with essential and hardworking field assistants. I thank the graduate students at UTC for always giving me emotional support (especially fellow Hayes students who accompanied me to remote field stations in Chile), and my friends who encouraged me to pursue a graduate degree. Finally, I thank my loving family, for always cheering me on, teaching me to say yes to every inspiring opportunity that comes my way, and without whom none of my dreams would be possible.


M. S.; A thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Master of Science.




Octodontidae; Degus; Rodents


Social organization; Social structure; Social network analysis; communal rearing; Fitness effects; Habitat conditions

Document Type

Masters theses




xvi, 113 leaves





Date Available