Undergraduate Honors Theses

Thesis Defended

Spring 2019

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Anthropology

First Advisor

Dr. Robin Miriam Bernstein

Second Advisor

Dr. Steven Leigh

Third Advisor

Dr. Deane Bowers

Abstract

This thesis examines the relationships between physiological factors of hair color, sex, nutritional health, and body size (mass) with measures of hair cortisol in domesticated Nicaraguan hunting dogs on the Bosawas Biosphere Reserve. Prior research on cortisol in dogs has been relatively limited to small, homogenous population samples under restricted environmental conditions. This leaves a gap in current knowledge, and a need for larger-scale studies to assess whether current understandings of how cortisol acts in dogs is applicable to dogs within dynamic and heterogeneous environments. The population of hunting dogs examined in this study live in an unpredictable environment in which disease, malnutrition, and mortality rates are high. Physical examinations were performed on each dog by a veterinarian during which a body condition score (BCS) was assigned, and measurements of size were taken, and medical and familial history were recorded. Hair samples were also taken to determine basal hair cortisol concentrations (HCC), and fur color was noted as light, dark, or agouti/mixed. Results showed that light HCC was on average significantly higher than dark and mixed HCC (p<.001). In addition, BCS scores and chest width were found to be negative effect on HCC (p<.001). In contrast with findings from prior studies, female dogs had significantly higher average cortisol levels than males (p=.016), suggesting sex differences in cortisol are present in domesticated dogs. The results of this study suggest a relationship between cortisol levels and BCS and body size, confirming previous findings and adding to the current understanding of physiological and nutritional variables of stress within dogs under varying environmental conditions. The results of this study are also relevant to current discussions within biology, ecology, and biological anthropology regarding the physiological effects of cortisol and evolutionary fitness.

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