Theses and Dissertations

Issuing Body

Mississippi State University


Belant, Jerrold L.

Committee Member

Leopold, Bruce D.

Committee Member

Wang, Guiming

Date of Degree


Document Type

Graduate Thesis - Open Access


Wildlife and Fisheries Science

Degree Name

Master of Science (M.S.)


College of Forest Resources


Department of Wildlife, Fisheries and Aquaculture


Many ecological and evolutionary processes have been described underlying natural selection but supporting evidence in wild settings is often lacking and our understanding remains incomplete. Using a multi-scale approach, I investigated expression of facultative den behavior (denning) among and within ursid species. Among species, lack of denning behavior was supported by relaxation of selection pressures of seasonal food availability due to realization of two sources of ecological opportunity; colonization of new habitat and adaptation of key innovations. Of denning species, I found evidence of adaptive ecological plasticity in den chronology among and within populations consistent with relaxed selective pressures influencing seasonal food availability and energetic budgets. I supported these finding using indices of fitness and established ecological theory. Further knowledge of organismal response to selection pressures has practical applications in predicting responses to novel and fluctuating pressures and aids in our understanding of the complexities of ecology and evolution.