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.
鈥淚t鈥檚 always something exciting or dramatic going on,鈥 said Yellowstone Wolf Project research associate Kira Cassidy.
(The number 907 refers to the wolf鈥檚 collar number. The F denotes female.聽
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鈥檚 wolf researchers have been able to observe interactions of the Junction Butte pack more closely than those living in remote regions.
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Adding to 907F鈥檚 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.
鈥907F has become the 鈥399 grizzly bear鈥 of Yellowstone wolves 鈥 people specifically coming to the park hoping to get a glimpse of this remarkable elder wolf,鈥 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.
The skull of 911M shows where his lower jaw was broken, months before he died.
You killed dad
The string of 907F鈥檚 unusual experiences begins in September 2016. That鈥檚 when the Prospect Peak pack killed 907F鈥檚 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鈥檚 dead body he weighed only 67 pounds, down from 102 pounds two years earlier. Further inspection revealed a for months, possibly when kicked in the head while chasing an elk.
Analysis of 911M鈥檚 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.
Kira Cassidy, Yellowstone Forever research associate, and Dan Stahler, the park's senior wildlife biologist, photograph wolf 1488M's teeth during a winter capture operation.
Sibling rivalry
The year after her father鈥檚 death, 907F ousted her sister, 969F, to become the lead female of the Junction Butte pack.
鈥淲e don鈥檛 often see packs where two females born in the same litter stay in their birth pack for their entire life,鈥 Cassidy said. 鈥淚 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鈥檛. Rarely did we see overt aggression.鈥
Wolf leaders are referred to as alphas. Usually, once that status is attained, the wolves maintain it throughout their lives, Cassidy said.
鈥淲ithin-pack tension is extremely rare,鈥 she said. 鈥淛unction does seem to have this strange pattern of the leadership position switching between wolves when the cause isn鈥檛 a death.鈥
As the alpha female, 907F mated with a male wolf from the rival Prospect Peak pack. 907F鈥檚 mate probably took part in the attack that killed his mate鈥檚 father.
鈥淚t鈥檚 fairly common for a male wolf to join a pack when they鈥檝e lost their male leader,鈥 Cassidy said. 鈥淪o two packs will fight, the male leader is killed, and then males from the attacking pack are allowed to join.鈥
The females in the pack have to approve, since the territory is passed down through the female line.
鈥淚t worked out for 907, because she has lived in the same pack territory her entire life because she did inherit that leadership role,鈥 Cassidy said. 鈥淢any 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.鈥
Junction Butte pack wolf 907F, at right, is shown in this 2023 aerial photo.
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.
鈥淲olves are mostly considered monogamous breeders where there鈥檚 one litter in the pack,鈥 Cassidy said. 鈥淏ut 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.鈥
When her pups were about 2 weeks old, 907F left the den. While she was gone, 969F killed all of her sister鈥檚 pups as well as the other mother鈥檚 young. 969F ate some of the young and buried others.
鈥淚t鈥檚 extremely rare, it actually has not been confirmed in other wild wolves, killing a packmate鈥檚 litters,鈥 Cassidy said. 鈥淏ut it probably does happen. We just happened to have such a great view of that Slough Creek den that we鈥檙e able to see things that are maybe pretty rare, but just haven鈥檛 been documented before.鈥
907F and her fellow pup-less mother than helped care for the other two wolves鈥 pups, 10 of which survived.
鈥淵ou 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,鈥 Cassidy said. 鈥淏ut this stuff that happens within the first few weeks of the pups鈥 life is just so hard because we see the dens so rarely.鈥
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.
鈥淭hat鈥檚 pretty rare,鈥 Cassidy said. 鈥淯sually 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.
鈥淪omething else was going on with her,鈥 Cassidy said. 鈥淲olves in this ecosystem so rarely die of straight starvation.
鈥淥ften they can find enough to scavenge on to at least be OK here, even by themselves.鈥
Likely blind in one eye from an injury or infection, wolf 907F is now 11 years old and more likely to take it easy than participate in hunts.
Matriarch
Despite these misfortunes, 907F has survived 11 years, one of only six Yellowstone wolves to record so many birthdays.
鈥淎ll of the other ones lived in places in the park where people can鈥檛 see wolves very easily, like down in the Delta, the Bechler or Cougar Creek,鈥 Cassidy said. 鈥907 is the only one of these uber elders 鈥 that is actually living in a place where people can see her regularly.鈥
The average lifespan for 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 12.5 years.
Mother supreme
Wolf 907F howls as she communicates with her pack.
Starting when she was 2 years old, 907F has given birth to 10 litters. One of 907F鈥檚 sons now leads a rival pack and two of her daughters are leaders of smaller packs.
鈥淥f the wolves we鈥檝e collared, we have confirmed that five wolves at least are 907鈥檚 direct offspring,鈥 Cassidy said. 鈥淭here鈥檚 probably another five to 10 of them out there that are her direct offspring.
鈥淭he 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.鈥
Last year the pack raised only one pup, and researchers are unsure who the mother is since the genetics have not been analyzed.
One sign of a female's alpha status is when they lift their leg to mark territory.
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.
鈥淏ut over the winter she looked great,鈥 she added. 鈥淚t could just be summer is actually a little harder on them. It鈥檚 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鈥檛 like the heat either. They鈥檙e much more comfortable when it鈥檚 really cold out.鈥
As she鈥檚 aged, 907F has transitioned away from dangerous hunts. Yet with her 9-year-old mate leading a relatively young pack 鈥 one yearling and five 2-year-olds 鈥 she still commands respect. Being the aunt or mother to the rest of the pack likely helps.
鈥淭hey see her as the boss,鈥 Cassidy said.
The elder wolf has also become more 鈥渂usinesslike鈥 and economic and efficient in her movements, the researcher noted, figuring out a way to be successful despite her advancing age.
鈥淪he鈥檚 often sleeping near the den, raising the pups, nursing them, but not leaving a whole lot.鈥
It also helps that the Junction Butte pack was large, containing 35 wolves in the winter of 2020.
鈥淭hat kind of makes them invincible to the rest of their neighbors,鈥 Cassidy said. 鈥淭here鈥檚 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鈥檛 really go many places.鈥
907F submissively licks the former alpha female, 1276F.
Even if she did wander outside her territory, it鈥檚 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鈥檛 travel much anyway, Cassidy noted.
鈥淏ut she is pretty elderly. Anything could happen. She could have a heart attack, or a blood clot or tumor and die tonight.鈥
