Date of Project

5-8-2021

Document Type

Honors Thesis

School Name

College of Arts and Sciences

Department

Biology

Major Advisor

Dr. Carrie Doyle

Second Advisor

Dr. Joanne Dobbins

Third Advisor

Dr. Amanda Krzysiak

Abstract

Cortisol is a hormone that is released in response to stress. Cortisol can be damaging in high amounts and it is ideal to maintain at a low level. Captive animals can experience high baseline levels of cortisol during their captivity, verses their non-captive counterparts, (Terio, Marker, & Munson, 2004). Enrichment, a stimulus that encourages an animal to perform natural behavior, is offered to captive animals to allow the animal to exhibit natural behaviors and hopefully lower stress levels. This experiment analyzes if exposure to a positive enrichment significantly impacts an animal’s fecal cortisol levels. Fecal cortisol levels are indicative of an animal’s stress levels, via hormones excreted in their waste.. A population of ten captive female tigers was monitored over the course of ten days. Ethograms – behavioral observations – were conducted daily to monitor the cohort of tigers during the entirety of the study. A positive enrichment, a hollowed-out pumpkin filled with chicken, was given by the keepers to five of the tigers. Feces was collected daily, and enzyme immunoassays performed to determine each of the individuals’ cortisol levels. Changes in the microbiome were also theorized, which will be analyzed in future studies. Approximately 60% of the individuals that received the positive enrichment had a drop in cortisol the following day, and 20% of the individuals that did not receive the positive enrichment also had a drop in cortisol. This study showed that there were daily fluctuations in cortisol among most of the cats involved in the study. This study indicates that some of the individuals, that received exposure to a positive enrichment, experienced a decrease in cortisol levels. Further studies are needed to establish if a low-stress population, like the individuals in the study, will show as substantial of a drop as a high-stress population. Future studies could assess if a high-stress population would benefit more from positive enrichment, than a low-stress population.

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