Activity budgets of zoo-living primates can vary by age-sex class, group size, and enclosure type. ZooTampa at Lowry Park had one of the largest AZA-managed Bornean orangutan (Pongo pygmaeus) groups until July 2023 when a family group of four individuals was transferred to Naples Zoo under SSP recommendation. Given that regular behavior monitoring is important for assessing individual welfare, this transfer provided a unique opportunity to investigate changes in individual activity budgets after a permanent change in group composition. Between February 2023 and February 2024, a team of students compared the behavior of the five individuals remaining at ZooTampa pre and post-transfer. We collected observations between 2:00 and 4:30 p.m., recording 12 state behaviors during 60-minute instantaneous scan samples at two-minute intervals. We compared 30 pre-move samples to 17 post-move samples using either an independent t-test or a Wilcoxon Rank Sum test, depending on normality, for each individual’s behavior. 

A general increase in activity was found for all individuals except the flanged male. The two juveniles showed an increase in foraging activity, and we observed an increase in self-grooming activity for the adults in the group. There were no changes in the percentages of social affiliative behaviors. Results suggest that the difference in activity budgets was influenced by the group fission event. The smaller group composition increased available space per individual and allowed for more frequent active behavior, especially for the juveniles. Change in group size may have led to increases in self-grooming, a stress-relieving behavior. The consistency in social behaviors might stem from the fact that the two familial groups (the one remaining at ZooTampa and the one transferred to Naples Zoo) generally kept their distance from each other.