Date of Award:

5-2026

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Daniel R. MacNulty

Committee

Daniel R. MacNulty

Committee

T.J. Clark-Wolf

Committee

Andre de Lima Moraes

Abstract

Sometimes predators don’t just affect prey by killing them, they can also change how prey behave. For example, animals may spend more time watching for danger and less time eating, which could affect their health and survival. In Yellowstone National Park, past research has suggested that elk may reduce feeding because they are trying to avoid predators like wolves and cougars. However, most previous studies have only looked at elk behavior during the daytime and have often looked at responses from single predators rather than multiple.

In this study, I used high-resolution tracking collars equipped with motion sensors to directly measure elk behavior continuously over a full 24-hour period. These data allowed me to determine when elk were feeding and examine how feeding changed in response to both where predators are likely to be and when they are most active.

I found that elk spent about 58% of their winter day feeding, and their feeding was spread throughout the day and night rather than concentrated at dawn and dusk. Predation risk from wolves and cougars was associated with small changes in feeding behavior, with slightly stronger effects in older individuals. However, these effects were very modest overall. These results suggest that while elk do adjust their behavior in response to predators, the changes in feeding time are relatively small. This means that predation risk alone is unlikely to strongly reduce feeding enough to impact elk populations at a large scale. More broadly, this study highlights the importance of measuring animal behavior continuously and directly to better understand how predators influence ecosystems.

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