Supposedly solitary pumas actually hang out with their fellow big cats quite often, frequently coming together and hissing and snarling before settling down to share a delicious elk carcass.
That's the startling discovery made by scientists who recently tracked 13 pumas — also called mountain lions or cougars — and set up cameras at kill sites. They recorded dozens of peaceful social interactions between these elusive felines.
Pumas can live for more than a dozen years in the wild and have huge home ranges that can stretch for hundreds of miles. Scientists used to think that they lived lonely lives and only came together to mate or fight over territory.
"There was really no other reason to come together at all," says Mark Elbroch of Panthera. "People just made a lot of assumptions based on very little data, and those assumptions became mythology, even within the science world."
But in the journal Science Advances, he and his colleagues say they had reason to suspect that the social lives of these mighty carnivores might be more complex. New GPS tracking that let scientists watch the movements of these animals in near real-time was revealing inexplicable meetings.
In May of 2012, for example, Elbroch looked at the GPS tracking and saw that a female and her kitten had stopped at a certain location. He noticed that another female with three kittens of her own were moving in that direction. So he and a colleague raced to the spot in the woods and found a dead elk. They pointed cameras at it and later found that the females spent two days together feeding at opposite ends of the same carcass.
"They sort of just sat at either ends of the carcass and weren't particularly friendly to each other. They just sat there and ate. And the kittens would bounce in and feed when they could," says Elbroch. "I can't explain how exciting it was for me to capture, for the first time, an interaction between adult mountain lions. It was just so different than what I expected to happen."
And it turned out to be a common occurrence. When they followed 13 of the big cats from April of 2012 to March of 2015, they learned that every single cat participated in food sharing. "All the mountain lions participated," says Elbroch. "That in itself was shocking. There wasn't a lone mountain lion that didn't interact with anybody."
In winter, the cats seemed to get together with pals over a meal every couple of weeks, in feeding episodes that could last for days.
"We found very clear, very interesting patterns to who shared with who," says Elbroch. The most dominant was direct reciprocity: if a mountain lion shared with another, the recipient would later return the favor.
What's more, the mountain lions generally seemed to organize themselves into a couple of small communities defined by the territories of two dominant males. Cats within these areas socialized more frequently with each other than with outsiders.
All of this, says Elbroch, "completely redefines what we know about mountain lions."
The study found that males, in general, received much more free food than they shared with others. It might be that females got something else in return, such as building a relationship that would provide breeding opportunities or protection from other males that might kill their young.
Given that mountain lions have a complex social system apparently built on reciprocity, Elbroch says this raises the question of whether other "solitary" carnivores do as well.
He also would like to know what effect trophy hunting might have on these social structures. "What happens when a male is removed," he wonders. "Is there social chaos? Is there quick turnover to maintain those social systems and relationships that are in place? We don't know."
RACHEL MARTIN, HOST:
OK. Now a story about the social lives of big cats. Mountain lions, also called pumas or cougars, have always been thought of as loners, but a new study reveals these cats actually have a hidden social life. NPR's Nell Greenfieldboyce reports that they frequently get together with neighbors to share a meal.
NELL GREENFIELDBOYCE, BYLINE: Mountain lions have been studied in North America for decades.
MARK ELBROCH: We have assumed that they're solitary killing machines and they're kind of like robots, they're all the same.
GREENFIELDBOYCE: Mark Elbroch is with a nonprofit called Panthera. He says scientists thought mountain lions came together only rarely.
ELBROCH: They were fighting over territory, or it was about courtship and mating between males and females, and there was really no other reason to come together at all.
GREENFIELDBOYCE: It turns out that's not true. Elbroch spent about three years tracking mountain lions in Wyoming with GPS collars that let him watch their movements in almost real time. When he saw big cat stop for a while, maybe because it had killed an elk, he and his colleagues would rush to the spot and set up motion-activated cameras. What they saw and heard astonished them.
(SOUNDBITE OF MOUNTAIN LIONS GROWLING)
GREENFIELDBOYCE: In this video, two females are facing off at a carcass. They snarl and swipe at each other.
(SOUNDBITE OF MOUNTAIN LIONS GROWLING)
GREENFIELDBOYCE: Then they settle down and peacefully share the meat. The researchers saw this happen over and over again. All the mountain lions shared food with neighbors.
ELBROCH: That in itself was shocking, you know, that there wasn't a lone mountain lion that didn't interact with anybody. They all participated.
GREENFIELDBOYCE: And who did they share with? In the journal Science Advances, the researchers say the lions followed a pattern of direct reciprocity - you give me some food, and later I'll give you some.
ELBROCH: It just highlights the fact that even a species like mountain lions, that we have studied for so long, we know so little about.
GREENFIELDBOYCE: And it makes him wonder about other supposedly solitary species. Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.