Document Type

Thesis

Date of Degree Completion

Spring 2026

Degree Name

Master of Science (MS)

Department

Primate Behavior

Committee Chair

Kara I. Gabriel

Second Committee Member

Lori K. Sheeran

Third Committee Member

Jessica Mayhew

Fourth Committee Member

Patti Ragan

Abstract

Environmental enrichment improves the welfare of captive animals. The primary aims of the current study were to investigate how captive orangutans interact with enrichment objects, their use of such objects in proximity to other orangutans, their choice of enrichment objects, and if age differences occurred in the use of enrichment. I collected 20 min focal samples of enrichment use in orangutan social groups at the Oregon Zoo (148 samples) and the Center for Great Apes (141 samples) using three ethograms on social context, object type, and manipulation behavior. Data shows that juveniles engaged in more social use of enrichment compared to adults. Captive orangutans interacted with structural and foraging devices more often than with other types of enrichment. Lastly, captive orangutans manipulated enrichment frequently via oral and play-on behaviors and infrequently using active tactile, nest, examine, tool use, tool manufacture, and carry. These findings provide insight into how orangutans interact with objects and may assist caregivers in constructing enrichment programs that meet developmentally associated and individual orangutan’s needs.

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Available for download on Thursday, July 03, 2031

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