A Yellowstone grizzly called Quill has been making his rounds with the females, but it hasn’t all been sweet romance.
It was all cuddly and snuggly when Quill and a well-known female, Snow, recently engaged in courtship.
The mood was decidedly different on Tuesday when Quill attempted to mate with another female, Grizzly 864, sometimes called the “Mud Volcano Sow.”
“He was actually biting her, wrestling with her. It was very aggressive,” grizzly watcher Kelly Ogilvie told Cowboy State Daily.
“I felt that he was getting frustrated and his aggression was escalating because she wasn’t receptive,” added Ogilvie, who lives in Idaho Falls, Idaho and frequently visits Yellowstone.
For male grizzlies, such behavior could be a survival of the fittest tactic, biologist Cecily Costello told Cowboy State Daily.
“Male reproductive success can be enhanced by them being aggressive,” said Costello, the statewide grizzly research biologist with Montana Fish, Wildlife and Parks (FWP).
Wrestling Throwdown
Estimated to be about 9 years old, Quill might be coming into his own as a top male bear in Yellowstone, Ogilvie said.
Listed by researchers as Grizzly 288, he’s been called Quill, because he showed up with a porcupine quill stuck under his left eye in 2024, said Ogilvie.
She’s a hobby wildlife photographer who watches bears in the Greater Yellowstone area, as well as in Alaska, Canada and Minnesota.
Grizzly 864 is estimated to be 13 years old and is roughly equal in size to Quill, she said.
She had one previous set of twin cubs that she raised to maturity. A second set of twins, born last year, didn’t survive, Ogilvie said.
Ogilvie said that she and others heard Quill and Grizzly 864 scuffling and roaring in the trees late Monday, but didn’t see them.
The two bears came into view on Tuesday, and Ogilvie captured video of Quill chasing the female, who would occasionally stop and brawl with him.
Quill was engaged in “relentless harassment,” she said. But at least on that day, it didn’t pay off for him.
“She would not put her rear end where it was available to him,” Ogilvie said. “I think that’s what was making him extremely frustrated.”
At one point, Quill tossed the female down onto her back.
“We were joking later that it was like a wrestling throwdown,” Ogilvie said.
She wondered if Grizzly 864 was not yet in “peak estrus” (heat) and therefore just not interested in mating at the time.
Whether the female finally gave in remained a mystery as of Thursday, she said. As far as Ogilvie knew, the pair hadn’t been spotted again after Tuesday’s display.
‘Single-Minded’
Grizzly mating season peaks in June, Costello said.
“Males can be relatively single minded this time of year and don’t take ‘no’ for an answer, she said.
“The males want to mate but the females have the ability to choose,” she said.
It’s not known for certain, but it could be that females’ estrus might be pushed into high gear by the presence of a persistent male, Costello added.
Whatever the factors driving female estrus might be, the males are hyper-focused on spreading their genes during mating season.
“They aren’t eating as much. They’re relying on their fat reserves. That’s why it’s important for males to come out of the den fat in the spring,” Costello said.
Ogilvie said that Quill’s throwdown with Grizzly 864 is the first time she’s seen him get aggressive during mating season.
Over the past couple of years, he’s courted Snow and her sister, Jam.
Snow and Jam are the daughters of Raspberry, perhaps Yellowstone’s most famous grizzly.
“Quill has courted Snow and Jam in a very relaxed manner,” Ogilvie said.
Mark Heinz can be reached at mark@cowboystatedaily.com.
