New research shows that fear of humans causes mountain lions to increase their energy expenditures as they move through the landscape, and this can ultimately limit the size of the home ranges they’re able to maintain.

«Mountain lions fear us, and that fear has all kinds of impacts on their behavior and ecology, and ultimately, potentially even their populations and conservation,» said professor Chris Wilmers, the senior author on the paper.

Wilmers is principal investigator for the Santa Cruz Puma Project, through which he and colleagues have been studying local mountain lion populations for over a decade. Barry Nickel, director of UC Santa Cruz’s Center for Integrated Spatial Research, led the most recent study, which relied on data from five adult female pumas and eight adult males that were outfitted with tracking collars as they roamed their natural habitats.

Throughout the two-month study period, the tracking collars recorded high-resolution GPS and accelerometer data, which Wilmers said worked «essentially like a Fitbit» to help the team estimate how many calories a mountain lion burned based on where, how far, and how fast the cat was moving. The ultimate goal was to integrate the energy cost of navigating physical terrain with the cost of avoiding humans to see how both factors affect use of habitats.

To assess the impacts of physical terrain, researchers compared topography with trends in the cats’ movement data. This showed that less rugged terrain requires less energy for pumas to navigate, which may help to explain why mountain lions prefer habitats with easy-to-traverse valleys or ridges. And to get a sense for how fear of humans affected the cats, researchers also compared housing densities with collar tracking data.

This analysis showed that, in areas with higher housing densities, pumas were engaging in more energetically demanding movements, like stopping less and moving more quickly. Their movements were also much less efficient: instead of taking the shortest path to their destination, they took longer, meandering paths to navigate around perceived risks.

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Materials provided by University of California — Santa Cruz. Original written by Allison Arteaga Soergel. Note: Content may be edited for style and length.