The study, published Nov. 15 in the journal Biological Conservation, found that mountain lions living in areas with higher levels of human recreation were more nocturnal than lions in more remote regions who were more active at dawn and dusk. The authors said their findings offer a hopeful example of human-wildlife coexistence amid a large, dense human population.

"People are increasingly enjoying recreating in nature, which is fantastic," said lead author Ellie Bolas, a Ph.D. candidate in the UC Davis Department of Wildlife, Fish and Conservation Biology. "This flexibility we see in mountain lion activity is what allows us to share these natural areas together. Mountain lions are doing the work so that coexistence can happen."

Mountain lions prefer to avoid people, but in a metro area of more than 18 million people, natural areas inhabited by mountain lions and other wildlife are also heavily used by recreationists. To learn whether and how lions were adjusting their activity in response to recreationists, the study authors monitored the movements of 22 mountain lions living in the Santa Monica Mountains and the surrounding region between 2011 and 2018.

The lions were captured and fitted with global positioning system (GPS) and accelerometer collars as part of a long-term study conducted by biologists at Santa Monica Mountains National Recreation Area, a unit of the National Park Service. The authors analyzed the collar data and quantified human recreation in the area using a global database of GPS-tracked activities that users opted to make public.