Heads up: The effects of age, sex, and group size on vigilance in white-tailed deer
Zachrey L. Swartzentruber, Elisa Howansky, and Chandler Russian
In response to the threat of predators, white-tailed deer (Odocoileus virginianus) alter their behavior to increase survival. One such behavior, vigilance, is costly but can increase fitness and help avoid predation. Our past research found that solo deer are more vigilant in open habitats and in areas with temporary human disturbance (THD). In this study, we tested whether group size, age, or sex affected vigilance. We also investigated whether group vigilance varied with habitat type or THD. We collected data from images captured by camera traps in Upstate South Carolina. Each observed deer was labeled vigilant if their head was higher than their back and not vigilant if their head was lower than their back. We hypothesized that adult deer would be more vigilant than juvenile deer and that females would be more vigilant than males. We also hypothesized that groups would be more vigilant than solo deer. Finally, we hypothesized that in groups, vigilance would be higher in more open habitats and in habitats with higher THD. In contrast to our hypotheses, we found that juvenile deer were significantly more vigilant than adult deer, and that males were significantly more vigilant than females. As predicted, we found that groups of deer were significantly more vigilant than solo deer. Habitat type had no significant effect on the vigilance of groups; however, groups were significantly more vigilant in areas with high THD than in areas with low THD. Our results suggest that deer in groups may be less vulnerable to predation because they are more vigilant than. Furthermore, the benefits of vigilance may outweigh the costs for juveniles, as well as for males. Overall, vigilance in white-tailed deer is complex and influenced by many different environmental and demographic factors.
Zachrey Swartzentruber is a senior biology major. He is a member of the TriBeta National Biological Honor Society and plans on pursuing a career in marine or ecological sciences.
Elisabeth Howansky, better known as Elisa, is a junior biology major pursuing a career in Biostatistics. They are a member of the Lander University Honors College and the Psi Theta chapter of TriBeta National Biological Honor Society.
Chandler Russian is a sophomore biology major. He is a member of the TriBeta National Honor Society. After graduation, he plans to attend medical school and become a primary care physician.