Abstract: Infectious disease plays a key role in regulating wild animal populations. Parasite infection has been correlated with differences in host behavior, decreased fitness, and increased risk of predation. In this study I used several standardized behavioral tests to determine which activity levels of Peromyscus are affected by intestinal parasite infection. Parasites can have both direct and indirect effects on the activities and behaviors of their hosts. We found that the presence of parasites does have a significant impact on several different activity levels. Cestodes were found to a negative impact on activity levels, decreasing open area awareness, average velocity, and number of jumps. These changes in behavior may be indirect effects of transmission but may also be direct effects meant to increase parasite transmission. Determining the reasons for the changes caused by parasites allows for better understanding of the impacts that disease may have on the demographics of animal populations.