Document Type


Date of Degree Completion

Spring 2023

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Dr. Jessica A Mayhew

Second Committee Member

Dr. Lori K Sheeran

Third Committee Member

Patricia Ragan


In the wild, orangutans live in individual fission-fusion social systems. This semi-isolated lifestyle means females act as sole caretakers of infants. However, recent social media posts from zoos and sanctuaries portray male orangutans engaging in behavior suggesting paternal involvement. In captivity, orangutans are often housed socially, allowing fathers to interact with offspring and raising the question of how orangutans may potentially demonstrate paternal behavior. This study examined interactions among immature offspring and their family groups in hybrid (Pongo pygmaeus x Pongo abelii) and Sumatran orangutans (P. abelii). Focal follows were conducted at two Association of Zoos and Aquariums and one Global Federation of Animal Sanctuaries accredited facilities, resulting in 168 hours of observation. Across all sites, male orangutans engaged in direct paternal behaviors such as playing, food-sharing, and contact, and indirect paternal behaviors such as proximity, tolerating, and defending. Across all sites, the immatures initiated significantly more interactions with their adult relatives than vice versa. Significant differences were also observed between interactions initiated by offspring and those initiated by their fathers, suggesting immatures drive interactions.

Available for download on Thursday, May 29, 2025