Date of Award

Spring 2019

Document Type

Thesis Restricted

Degree Name

Master of Arts (MA)



Committee Chairperson

Rebecca Chancellor, Ph.D.

Committee Member

Aaron Rundus, Ph.D.

Committee Member

Susan Gans, Ph.D.


Positive reinforcement training (PRT) is a method commonly used by animal caretakes to decrease stress in captive animal associated with routine medical and maintenance procedures. While PRT has been shown to decrease displays of stereotyped behaviors and cortisol concentrations, aspects of the training such as interaction with humans and disruption of natural behaviors can be a cause of stress. Cortisol is a simple way to measure the physiological response to a stressor. Salivary cortisol reflects the short-term response to an acute stressor. To determine if PRT sessions would cause a change in cortisol concentration, saliva samples were collected before and after training sessions from 11 chimpanzees at the Maryland Zoo in Baltimore. Cortisol concentration was determined by enzyme-linked immunosorbent assay, and differences in concentration were calculated by subtracting the cortisol level before training from the level after. Results of a Wilcoxon signed-rank test showed no significant difference between the mean difference for each chimpanzee and zero, suggesting that PRT sessions have no effect on cortisol concentration.