JACKSON, Wyo. — New research has debunked theories as to why mountain lions in northwest Wyoming seem to be eschewing their normal solitary habits.
The theories included that the lions were associating with each other because their home ranges were near their siblings or parents.
But it turns out that hypothesis was wrong, said Mark Elbroch, team leader of the Teton Cougar Project, which studies the big cats. “In fact, what we found is that interactions occur between the least-related individuals most often,” Elbroch said.
The results were recently published in the academic journal Acta Ethologica.
Some years back, two mother lions with kittens tracked by the Cougar Project were seen “plainly hanging out” with each other consistently for months.
“Every time one of them made a kill, the other one would show up,” Elbroch said. “The assumption and the story was that they must be sisters.”
Instead, genetics tests proved that the two female felines were as “unrelated as they could be,” he said.
Researchers based their findings on GPS location data from 18 Jackson Hole-area cats and DNA tests from 68 animals.
Over the course of an eight-year period, the Cougar Project detected 92 “spatial associations” between GPS-collared cats, defined as any time when two animals were
within 200 meters of each other
for four hours or less. It documented another 190 “spatial overlaps,” defined as a period when cats were within 200 meters of each other
for between four hours and two weeks.
Associations were nearly seven times more frequent during the breeding season — Feb. 1 to July 31 — compared with the rest of the year.
But that seasonal rise is not just because of male and female lions are mating, Elbroch said. It can also be attributed to fluctuations in the whereabouts of prey.
“Winter’s a big deal here,” he said. “There’s deep snow, serious ungulate (large-mammal) migrations, large congregations of elk. This changes everything for mountain lions, including where they
The Acta Ethologica paper uses the word “associations” rather than “interactions” because of limitations that Elbroch is up front about. The Cougar Project study relied only on hard data acquired from GPS collars and did not attempt to weave in observations made via remote video camera.
But an analysis of cougar relations from the video feed, which includes 50 adult cat interactions, is coming soon, Elbroch said.
“No one knows what these guys are doing,” he said. “It really creates a mythology.”