the Jackson Hole News & Guide-- click here (http://bit.ly/WMolfx) --READ FULL STORY
Cougars not so solitary, Teton researchers find
Jackson Hole’s lions hang out together more than expected.
POSTED: WEDNESDAY, JULY 23, 2014 4:30 AM
For years there has been talk around Jackson Hole of mountain lion “prides” that has run against the grain of the conventional belief that the large felines are a purely solitary species.
Perhaps, researchers with the Teton Cougar Project pondered, lions were teaming up to better defend themselves against wolves. Or maybe it was because elk and deer were falling off in numbers, forcing cougars to share finite food sources. Possibly, the biologists hypothesized, the social behavior was because the cats’ home ranges were near those of siblings or parents, and they were associating with their own blood.
It turns out that all of those hypotheses were flat wrong, Cougar Project team leader Mark Elbroch said.
“What’s really exciting about science — when it actually works — it’s that you can test these ideas,” Elbroch said. “I thought of [the study] as a wonderful example of science at work.”
Using GPS location data from 18 Jackson Hole-area cats and DNA tests from 68 animals, the Kelly-based Teton Cougar Project crunched the numbers and affirmed that local lions were social. But their associations with one another were not at all driven by more wolves, less food or the proximity of relatives.
The results were recently published in the academic journal Acta Ethologica.
“In fact,” Elbroch said, “what we found is that interactions occur between the least-related individuals most often.”
Some years back, two mother lions with kittens tracked by the Cougar Project — F51 and F61 — 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.
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. Another 190 “spatial overlaps” were documented, defined as a period when cats were within 200 meters of each other for between four hours and two weeks.
Male and female cats associated most of the time, followed by females rubbing shoulders with other females.
Males were tracked within 200 meters of one another just six times in eight years, a rate of association that was “statistically insignificant,” the Acta Ethologica paper said.
Associations were nearly seven times more frequent during the breeding season — February 1 to July 31 — compared with the rest of the year. That seasonal rise is not just because of male and female lions are canoodling, 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 migrations, large congregations of elk.
“This changes everything for mountain lions, including where they are.”
The Acta Ethologica paper uses the word “associations” rather than “interactions” because of some 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.”“What I’m excited to do is address this mythology directly,” Elbroch said. “What are they doing? Are they fighting? Are they mating?”
Posts
No comments:
Post a Comment