Editor’s Note: This is the second blog in a pair of blogs about a paper recently published in Science Advances showcasing collaborative research with Drs. Mark Lubell and Michael Levy of UC Davis, and Dr. Anthony Caragiulo of the Sackler Institute for Comparative Genomics at the American Museum of Natural History. The paper provided the first evidence of complex social strategies in a solitary carnivore, and showed that mountain lions are more social than previously thought. Part One chronicled reciprocity among mountain lions tolerating each other and food-sharing within mountain lion “networks.”
Direct reciprocity—I give you something, and in return, you give me something—was the strongest pattern we discovered while analyzing mountain lion social tolerance and food-sharing near Jackson, Wyoming. But reciprocity wasn’t painted broadly across the local mountain lion population—it occurred primarily among smaller groups. We were fascinated to see that these smaller communities were governed by resident male mountain lions and characterized by boundaries painted on the ground—much like “neighborhoods.”
In many ways, our neighborhoods define us and govern our routines and social relationships. The people of Jackson, Wyoming, for example, are also members of neighborhoods. Residents of Cottonwood Park buy food at nearby Smith’s and Whole Grocer and meet friends at Pizza Artisan. Their children walk to Colter Elementary School. Folks in East Jackson, by contrast, are more likely to shop at Lucky’s, meet for pizza and cheer at Pinky G’s or Pizza Caldera, and walk their kids to Jackson Elementary School.
It’s not that we can’t break free and shop and socialize where we like, but typically, we don’t. Perhaps it should be no surprise that mountain lions are just the same.
Number 1 of 3 videos in sequence: In the above video, F51, an adult female mountain lion vocalizes as M29, the resident male in the top photograph, pays her a visit at her kill. The two videos below follow in sequence so you see what happens.
Mountain lions sharing a neighborhood hunt the same herds, wander the same paths, allow their kittens to play on the same log fortresses, and—now we know—socialize and share food with other members of their neighborhood far more than they do with mountain lions in adjacent neighborhoods.
Mountain lion neighborhoods, in contrast to our own city planning, are defined by the spatial boundaries of territorial males. In this way, males influence which mountain lions interact with which mountain lions. You might think of territorial males like mayors or governors of fiefdoms, each of which range on average 220 square miles (570 km2) in our study area.
Or maybe it would be better to think of them as the Neighborhood Watch, constantly patrolling to enforce their boundaries, interacting with the females that live in their neighborhoods, and occasionally sub-adult females and males, as well.
Number 2 of 3: M29 circled around and very slowly enters frame. Note that his ears are forward and he is not aggressive, which we learned was very normal male behavior during social encounters. F51, by comparison, hisses and snarls and appears very defensive. At the time, she had 3 6-week old kittens stashed in a log about 100 meters away. Genetics confirmed M29 was their father.
The question, then, is what happens to the social organization of mountain lions when a territorial male dies? We don’t know to be honest, but we can speculate based upon research conducted on other species.
When it’s a “natural” takeover, where a younger, stronger male mountain lion displaces an old, failing male, we suspect that social patterns remain intact. But if a male dies unexpectedly, struck by a vehicle on a road, victim to poisoning or disease, or shot by a human hunter, there may be a period of time in which no mountain lion is acting as Neighborhood Watch. We’ve seen slow male replacement in our study area, for example, where mature males are in short supply.
We don’t completely understand what happens to mountain lion social organization when a territorial male is absent. Brown (grizzly) bears, for example, suffer social disruption for up to two years after an adult male is killed by a hunter, during which neighboring males sometimes invade and kill cubs they did not sire. Similar social disruption has been suggested for mountain lions under heavy pressure from hunting, and social chaos born of heavy hunting has been linked to increased mountain lion-livestock conflicts, as well.
Number 3 of 3: M29 relaxes and rolls about, with a slightly tense F51 lying nearby. The pair spent 6 hours together, alternately feeding on the elk killed by F51. On his departure, M29 visited the site where F51 stashed her kittens. We did not have a camera there, so cannot describe what happened. But he did not harm the kittens. F51 remained to continue to feed from the elk for 2 more days.
Whereas there’s been considerable research on the effects of hunting on the numbers of mountain lions, there has been little research on any other effect of hunting. We believe an important point of our research was in highlighting the need to prioritize new research on the effects of hunting on mountain lion social behaviors and social organization, to better understand and improve our conservation and management of this amazing animal.
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