Toni Ruth conducted the second of three major cougar studies in Yellowstone National Park. The first Yellowstone cougar study was led by biologist Kerry Murphy between 1987 and 1996, pre-wolf days.
Ruth’s study took place after the wolf reintroduction in the Park and her aim was to understand how wolves might be affecting cougars, since their prey overlap.
Working under the auspices of the Hornocker Wildlife Institute/Wildlife Conservation Society, Ruth radio-collared eighty-three cougars between 1998 and 2006.
Trudging through the deep Yellowstone snow, Ruth found that cougars were killing mostly elk, the major prey during the winter months in the northern area of the Park. But a few of Ruth’s collared lions also became experts in killing other animals as well as their primary winter diet of elk.
One surprise from the study was a collared lion who had a penchant for coyotes. The study was monitoring a female lion who had two seven-month kittens traveling with her.
The wolves had made a kill in the Sluice Creek valley, which they’d subsequently left a few days earlier. When this female lion approached the kill site, the researchers wondered what she was doing. “That’s pretty risky behavior.
She must not be doing too well,” they thought. The following day the researchers, monitoring her collar activity, noticed she brought her two young kittens to the kill site. “What is she doing? This is crazy behavior because the wolves may not be at the kill, but they certainly aren’t too far off either.”
When the researchers approached the kill site to their surprise they found two dead coyotes. Analyzing the snow track evidence, Ruth determined that this cougar never did scavenge on the kill.
Instead, she just hung out to the side of the kill, ambushed the coyotes, and then went back to retrieve her kittens to feed on them.
That same female repeated this behavior from under the Lamar Bridge. The lioness sat on the south side of the bridge, watching a group of coyotes on the opposite bank up the hill.
With the river frozen, she emerged from behind a tree, crossed the river and went into a stalk. As she inched closer, she ambushed one coyote, drug it under the trees where she cached it. She then returned with her kittens to feed on her kill.
These kinds of stories and more will be in my upcoming book Ghostwalker: Tracking a Mountain Lion’s Soul through Science and Story due out in 2018.