An animal’s particular level of dominance within the group that they live with has been observed by various studies on its impact in regards to obtaining food, finding sexual partners, and how conflict is dealt with. Macaca fascicularis is a species of primate found all over Southeast Asia in countries such as Malaysia, Indonesia, India, Vietnam, and Thailand. They are most commonly known as long-tailed macaques. Studies show that they are matrilineal the males leave tend to leave their groups upon sexual maturity, preserving an abundant of female to male ratio. Studies show that the more dominant males within groups containing multiple males are given higher priority for the access of essential elements such as food and mate selection, sustaining the fitness of the individual. The males who are dominant to the other males should displaying aggressive behavior such as biting, kicking, directed vocalization, lunging, chasing, and threatening gestures suggesting imminent attack whilst the submissive male must in turn perform a submissive behavior. These include lip smacking, fleeing, avoiding, vocalization, or grimacing. We found, through open field observance, that between the only two adult male long-tailed macaques that lived in the observed group, that there was a significant difference in perceived dominance based on agonistic and submissive interactions. Also, the dominant male spent significantly more time engaging in sexual behavior than the submissive male, which aids the supporting the hypothesis that there is a link between dominance and frequency of sexual behavior in groups of long-tailed macaques. The observations that made helped discern how aggressiveness impacts the lives of male animals and their ability to survive and reproduce and provided data on group dynamics, which is important to the overall management of the island population. Supported in part by the UW Center for Global Field Study; PSSP-IPB, Indonesia.