Queen of the wolves: One-eyed 11-year-old defies difficulties in a wild Yellowstone

Neither Greek nor Shakespearean tragedies, or even violent Mafioso movies, can rival some of the scenarios wolf 907F has faced while living in the northeastern corner of Yellowstone National Park.

“It’s always something exciting or dramatic going on,” said Yellowstone Wolf Project research associate Kira Cassidy.

The number 907 refers to the wolf’s collar number. The F denotes female.

Born into the Junction Butte pack in the spring of 2013, 907F suffered from a slight outbreak of mange that left half her tail without hair. Despite being smaller than her littermates, Cassidy described the wolf as playful, always trying to engage her family.

Because the pack roams an area of the park close to traffic and often dens across from a road along Slough Creek, Yellowstone’s wolf researchers have been able to observe interactions of the Junction Butte pack more closely than those living in remote regions.

Adding to 907F’s mystique and popularity with tourists, for almost half her life she has suffered from either an injury or infection that appears to have left her blind in one eye.

“907F has become the ‘399 grizzly bear’ of Yellowstone wolves – people specifically coming to the park hoping to get a glimpse of this remarkable elder wolf,” said Taylor Rabe, a wildlife technician with the Wolf Project.

399 is the matriarch of grizzly bears in Grand Teton National Park, giving birth to 18 cubs in her 28 years.

You killed dad

The string of 907F’s unusual experiences begins in September 2016. That’s when the Prospect Peak pack killed 907F’s father, 911M. He was the founder of the Junction Butte pack. At the time of his death, 911M was limping and malnourished.

When scientists examined the male wolf’s dead body he weighed only 67 pounds, down from 102 pounds two years earlier. Further inspection revealed a jaw that had been severely broken for months, possibly when kicked in the head while chasing an elk.

Analysis of 911M’s bone marrow showed he had only 10% body fat. Anything less than 20% is considered starvation, Cassidy said.

Despite these injuries, 911M had brought down an injured cow elk. While feeding, the rival pack arrived to defend their territory and claim the carcass. Rather than run, 911M stood his ground and was killed.

Clashes between wolf packs are the leading natural cause of wolf deaths in Yellowstone. The leading cause of death, about 77%, is human related.

Sibling rivalry

The year after her father’s death, 907F ousted her sister, 969F, to become the lead female of the Junction Butte pack.

“We don’t often see packs where two females born in the same litter stay in their birth pack for their entire life,” Cassidy said. “I think that may have contributed to some tension between them. There were times when they would switch which one of them was the pack leader and which one wasn’t. Rarely did we see overt aggression.”

Wolf leaders are referred to as alphas. Usually, once that status is attained, the wolves maintain it throughout their lives, Cassidy said.

“Within-pack tension is extremely rare,” she said. “Junction does seem to have this strange pattern of the leadership position switching between wolves when the cause isn’t a death.”

As the alpha female, 907F mated with a male wolf from the rival Prospect Peak pack. 907F’s mate probably took part in the attack that killed his mate’s father.

“It’s fairly common for a male wolf to join a pack when they’ve lost their male leader,” Cassidy said. “So two packs will fight, the male leader is killed, and then males from the attacking pack are allowed to join.”

The females in the pack have to approve, since the territory is passed down through the female line.

“It worked out for 907, because she has lived in the same pack territory her entire life because she did inherit that leadership role,” Cassidy said. “Many other wolves, if they want to become a breeder or a leader, have to disperse at some point in their life, start a new pack or join one. And she never had to do that.”

Infanticide

Cassidy said as the sibling sisters grew older, tension between them seemed to increase.

In the spring of 2019, the pack had four litters from different females.

“Wolves are mostly considered monogamous breeders where there’s one litter in the pack,” Cassidy said. “But every year about a quarter of the packs in Yellowstone have more than one litter. And Junction Butte has been one of those that is very consistently having two or three or more litters each year.”

When her pups were about 2 weeks old, 907F left the den. While she was gone, 969F killed all of her sister’s pups as well as the other mother’s young. 969F ate some of the young and buried others.

“It’s extremely rare, it actually has not been confirmed in other wild wolves, killing a packmate’s litters,” Cassidy said. “But it probably does happen. We just happened to have such a great view of that Slough Creek den that we’re able to see things that are maybe pretty rare, but just haven’t been documented before.”

907F and her fellow pup-less mother then helped care for the other two wolves’ pups, 10 of which survived.

“You would never suspect any other pack that shows up with 10 pups by the end of the summer, we just assume they had 10 or a couple of others were lost,” Cassidy said. “But this stuff that happens within the first few weeks of the pups’ life is just so hard because we see the dens so rarely.”

A year later, 969F died, possibly from starvation that was exacerbated by an illness. At the time she had been on her own for a couple of months.

“That’s pretty rare,” Cassidy said. “Usually wolves are killed by other wolves when they are otherwise perfectly healthy.”

A necropsy showed 969F had suffered injuries inflicted by other wolves, possibly from her own pack, as well as old injuries. Her bone marrow was at 42%, considered fair to poor. She weighed only 73 pounds.

“Something else was going on with her,” Cassidy said. “Wolves in this ecosystem so rarely die of straight starvation.

“Often they can find enough to scavenge on to at least be OK here, even by themselves.”

Matriarch

Despite these misfortunes, 907F has survived 11 years, one of only six Yellowstone wolves to record so many birthdays.

“All of the other ones lived in places in the park where people can’t see wolves very easily, like down in the Delta, the Bechler or Cougar Creek,” Cassidy said. “907 is the only one of these uber elders … that is actually living in a place where people can see her regularly.”

The average lifespan for wolves in Yellowstone is four to five years. That drops to two to three years outside the park. The oldest known wolf in Yellowstone was also a female, 478F of the Cougar Creek pack, who lived 121/2 years.

Mother supreme

Starting when she was 2 years old, 907F has given birth to 10 litters. One of 907F’s sons now leads a rival pack and two of her daughters are leaders of smaller packs.

“Of the wolves we’ve collared, we have confirmed that five wolves at least are 907’s direct offspring,” Cassidy said. “There’s probably another five to 10 of them out there that are her direct offspring.

“The first three or four of her litters did not do well. I think most of them died before the end of the year, or before they got into their first winter. She really started to be successful starting in about 2020, and then she had a string of very successful years.”

Last year the pack raised only one pup, and researchers are unsure who the mother is since the genetics have not been analyzed.

Semi-retired

While flying over wolf packs during surveillance last summer, Cassidy said 907F resembled an elderly dog with less muscle mass and slower, arthritic movements.

“But over the winter she looked great,” she added. “It could just be summer is actually a little harder on them. It’s harder to kill big prey, because the prey is in better shape, especially late summer into the fall, even early winter. And the wolves don’t like the heat either. They’re much more comfortable when it’s really cold out.”

As she’s aged, 907F has transitioned away from dangerous hunts. Yet with her 9-year-old mate leading a relatively young pack – one yearling and five 2-year-olds – she still commands respect. Being the aunt or mother to the rest of the pack likely helps.

“They see her as the boss,” Cassidy said.

The elder wolf has also become more “businesslike” and economic and efficient in her movements, the researcher noted, figuring out a way to be successful despite her advancing age.

“She’s often sleeping near the den, raising the pups, nursing them, but not leaving a whole lot.”

It also helps that the Junction Butte pack was large, containing 35 wolves in the winter of 2020.

“That kind of makes them invincible to the rest of their neighbors,” Cassidy said. “There’s no chance that another pack is going to come in and beat them up. So she can kind of go anywhere. Although at this point she doesn’t really go many places.”

Even if she did wander outside her territory, it’s likely that an individual in one of the surrounding packs is either a close or distant relative who may allow her safe passage.

Whether 907F will survive another winter and make a bid to be the oldest wolf in Yellowstone is impossible for Cassidy to predict. The old wolf has a few things in her favor for the next few months. Wolf-on-wolf deaths decline in the summer and 907F doesn’t travel much anyway, Cassidy noted.

“But she is pretty elderly. Anything could happen. She could have a heart attack, or a blood clot or tumor and die tonight.”