First Advisor

Randy Zelick

Date of Award


Document Type


Degree Name

Bachelor of Science (B.S.) in Biology and University Honors




Orangutans -- Behavior -- Case studies, Zoo visitors, Animal welfare, Orangutans -- Effect of human beings on, Human-animal relationships, Zoo animals




The Oregon Zoo is home to many exotic animals, including Bornean and Sumatran orangutans. They live in a relatively new naturalistic exhibit and are subject to large volumes of visitor traffic throughout the day. This is a pilot study to determine the variables and details necessary to conduct a more in depth analysis of orangutan welfare in the future. Eleven behaviors were observed to create an activity budget for the orangutans to be used to analyze the effect of different variables on their behavior. The independent variables examined were crowd size, temperature, weather, test day, and individual (in regards to the orangutan). The behaviors focused on with relevance as potential welfare indicators were time spent looking at visitors, covering head, and time not visible. Behavior data in rainy and sunny weather were subsequently compared to determine if certain behaviors were responding to weather or other variables. Large crowd size was found to be correlated with decreased time spent not visible and increased time spent covering head when weather was sunny. Additionally, large crowd size was correlated with decreased time spent not visible and covering head in times of rainy weather. However, crowd size did not have a significant effect on these variables. A larger sample size needed to detect significance in the effect of independent variables on the dependent variables with the given amount of variance. Additional methods such as hormone testing, and including other variables such as exhibit design, social system, and other visitor variables would be helpful in creating a more thorough analysis of the welfare of the animals.


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