MARY LOUISE KELLY, HOST:
The city of Los Angeles shares an interesting feature with Mumbai in India. They are the only two megacities where humans and big predatory cats coexist within city limits - in Mumbai, it is leopards; in LA, the mountain lions. New research on LA's big cats suggests that they are adjusting their schedules to make city life more peaceful, since they share their habitat with hordes of hikers and bikers and trail runners. That is the conclusion of a seven-year study of the mountain lions' behavior. It is now out in the journal Biological Conservation, and Ellie Bolas is the lead author. Ellie Bolas, welcome.
ELLIE BOLAS: Thank you so much for having me.
KELLY: So I was reading - I saw you and your team tracked 22 mountain lions with special GPS collars, and then you analyzed their movements and looked at it in relation to all the human activity around them. What's the headline on what you found?
BOLAS: Yeah. So we found that mountain lions in the Los Angeles area are actually changing the timing of their activity to adapt to human recreation by becoming more nocturnal and resting during the day in areas where there's more recreation happening.
KELLY: And how much more - to what degree are they doing this?
BOLAS: Generally, the mountain lions that live in areas with a lot of recreation - for example, Griffith Park or the Verdugo Mountains - are less likely to be active around dawn or dusk...
KELLY: OK.
BOLAS: ...And are more likely to be active at nocturnal times. During daylight, they spend about one more hour resting as compared to the mountain lions that live in more remote areas like the Santa Susana Mountains.
KELLY: Can I digress for a minute? (Laughter) How do you collar a mountain lion? Like how do you...
BOLAS: (Laughter).
KELLY: ...I gather you've actually done this? How do you even find them, given how elusive they are?
BOLAS: The National Park Service at the Santa Monica Mountains National Recreation Area has actually been studying mountain lions in the greater LA area for over 20 years. It takes a lot of effort and time to figure out where the mountain lions are and get them into a trap. And then we, very carefully, will sedate them and deploy the GPS collar and make sure they're healthy and send them on their way.
KELLY: OK, let me move you to what it means for the mountain lions. Does a shift to more nocturnal behavior help their ability to hunt? Does - how does it impact their ability to find food and survive?
BOLAS: So the great thing is that mountain lions are already nocturnal animals. So this shift in activity seems a pretty easy move for them. But the issue here is that animals need to spend a certain amount of time every 24-hour period being active, so they can hunt, travel around their territories. And so small changes in activity may impact how much energy they have for those activities.
These animals are also contending with busy roadways and habitat fragmentation, wildfires, exposure to rodenticides. So those are really stressful for mountain lions. And even something small, like changing the timing of their activity, is adding stress to an already stressed population.
KELLY: Is there anything people should keep in mind - people in LA or anywhere else - when we are out hiking, biking, driving in natural lands to minimize the impact on big cats and other wild animals that are also calling those places home?
BOLAS: Yeah, you know, I also recreate in the Santa Monica Mountains. And the reality is we don't actually get to see most wild animals when we're out and about very often because they're trying to avoid us. So I think it's important that we're aware that these are shared landscapes.
It's good for us to know that they're more active at dawn and dusk and at night, particularly when we are driving these mountain roads because roadways are actually a main source of mortality for mountain lions in the LA area. But I think, generally, we can just feel a sense of optimism that mountain lions are so flexible in their activity and working hard to avoid us so that we can share these spaces together.
KELLY: Ellie Bolas, Ph.D. candidate at the University of California, Davis. Thank you.
BOLAS: Thank you so much for having me.
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