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Research on captive animals reaps substantial benefits for conservation, education, and enrichment efforts. As more species become displaced in their natural habitats, it is the job of the researcher to better understand how these animals behave in captivity. To contribute to these efforts, we have been observing the activity budgets of a group of captive western lowland gorillas (Gorilla gorilla gorilla) (1 adult male, 2 subadult males, 2 adult females, 2 infant/juveniles) at the Philadelphia Zoo. Over a period of 16 non-consecutive months, we conducted 30-minute focals with 2-minute scan samples on the gorillas (54.66 hours), recording time of day, specific behaviors, temperature, and level of activity in their outdoor enclosure. We categorized behaviors as either low activity (e.g., laying down, self-grooming, sitting, and standing), or high activity (e.g., foraging, moving/traveling, nest building, chasing, playing, and self-scratching). We predicted that warmer temperatures as well as later time in the day would decrease the activity level of the gorillas. Our results showed a non-significant relationship between temperature and activity budget (F1,79 = 0.059, p = 0.8, R2 = 0.001). We also found a non-significant relationship between time of day and activity budget (t79 = 0.637, p = 0.5). Our results suggest that temperature and time of day have little to no effect on the gorillas’ activity level. We discuss ways that this research could be expanded upon in the future to further our understanding of how best to care for captive gorillas.