Degree Name
MS (Master of Science)
Program
Geosciences
Date of Award
5-2020
Committee Chair or Co-Chairs
Steven C. Wallace
Committee Members
Timothy A. Joyner, Christopher C. Widga
Abstract
This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most radically altered environment, the city, experience the strongest selection for encephalization. Urban raccoons studied here exhibit a higher EQ. Although results are preliminary, data suggest that encephalization is accelerated during abrupt periods of environmental change. Finally, implications for the evolution of biological complexity more generally are discussed.
Document Type
Thesis - unrestricted
Recommended Citation
Anderson, Peter M., "Encephalization in Commensal Raccoons: A Unique Test of the Cognitive Buffer Hypothesis" (2020). Electronic Theses and Dissertations. Paper 3720. https://dc.etsu.edu/etd/3720
Copyright
Copyright by the authors.
Included in
Behavior and Ethology Commons, Evolution Commons, Paleobiology Commons, Paleontology Commons, Zoology Commons