Examining Paternal Care in Captive Sumatran and Hybrid Orangutans.

In the wild, orangutans live in an individual fission-fusion social system. This semi-isolated lifestyle means females are the sole caretakers of infants. However, recent social media posts from zoos and sanctuaries depict adult male orangutans engaging in behavior suggesting paternal involvement in offspring care. In captivity, orangutans are often housed socially, allowing fathers to interact with their offspring and raising the question of whether, and how, orangutans may potentially demonstrate paternal behavior. We examined interactions among immature offspring and their family groups in captive, hybrid (Pongo pygmaeus x abelii) and Sumatran orangutans (Pongo abelii). We conducted 168 focal follows on three immature orangutans from three separate family groups. Across all three locations, male orangutans engaged in direct paternal behaviors, such as playing, food-sharing, and contact, and indirect paternal behaviors such as proximity, tolerance, and defense. Immature orangutans at all three sites initiated significantly more interactions with their fathers than vice versa. Significant differences were also observed between the number of interactions initiated by offspring and those initiated by their fathers, suggesting that immatures drive interactions. These findings demonstrate that some captive male orangutans engage in paternal care of their offspring and, when given the opportunity, offspring take advantage of the presence of their fathers as partners in social interactions. This study emphasizes the importance of making observations across multiple contexts and group compositions to better understand the behavioral and social diversity of orangutans.