The subordinate females of the Druid Peak pack killed their own alpha in the spring of 2000. It was the first documented case of intra-pack killing in the history of the Yellowstone wolf reintroduction.
The alpha they killed was 40F, and she had been running the Druid Peak pack through violence since the day the pack was released into the Lamar Valley in April 1996. The original Druid pack was captured near Fort St. John in British Columbia and consisted of five wolves: an alpha pair, 38M and 39F, and their three daughters, 40F, 41F, and 42F. Within the first year, 40F had driven her own mother out of the pack. 39F left and became a lone wolf. 41F followed shortly after, likely forced out by the same pressure. 40F installed herself as alpha female, and the pack she ran from that point forward was governed by sustained, targeted physical abuse directed primarily at one animal: her sister 42F.
Yellowstone researchers nicknamed 42F "Cinderella." The name was not sentimental. It was descriptive. 40F attacked her sister routinely and without obvious provocation. The beatings were documented over multiple years by wolf biologists and the hundreds of visitors who watched the Druid pack daily from the roadside pullouts in the Lamar Valley. 42F was frequently observed with visible wounds and fresh blood from her sister's attacks. In 1998, 42F denned and produced pups. None survived. In 1999, 40F attacked 42F directly in her den. She produced no pups that year either.
In the spring of 2000, three females denned: 40F in the traditional Druid den, 42F to the west, and a subordinate niece, 106F, to the east. All three had been bred by the pack's alpha male, 21M, a black-coated wolf from the Rose Creek pack who had joined the Druids in 1997 after their original males were illegally shot outside the park.
Sometime in May, the subordinate females turned on 40F. The exact sequence was not directly observed, but the result was unambiguous. 42F and several of the pack's younger females, nieces of both 40F and 42F, attacked and killed the alpha. Researchers found 40F dead, covered in bite wounds inflicted by her own pack. It was the first confirmed intra-pack killing in Yellowstone since reintroduction.
What happened next is the part of the story that researchers still talk about.
42F moved her pups from her own den into 40F's now-empty den. Then she took in 106F and her pups as well. Three separate litters, twenty-one pups in total, consolidated under one female who had spent years being beaten by the animal she had just helped kill. Under the leadership of 42F and 21M, twenty of those twenty-one pups survived the year. The Druid Peak pack grew to thirty-seven wolves, one of the largest packs ever recorded in Yellowstone or anywhere else.
42F and 21M led the Druids through what researchers and wolf watchers consider the golden years of the pack. They were visible daily from the Lamar Valley road. Over a hundred thousand visitors watched them hunt elk, contest territory with rival packs, and raise successive generations of pups in full view of spotting scopes. The pair was featured in three National Geographic films. Yellowstone biologist Doug Smith described them as a classic couple.
42F was killed in February 2004 by wolves from the Mollie's Pack in a territorial attack on Specimen Ridge. 21M died four months later of old age, on the same ridge, overlooking the Lamar Valley he had dominated for six years. One of the pups 42F had adopted after killing her sister eventually produced a daughter who grew up to become one of the most famous wolves in Yellowstone history: the wolf known as 06.

Doing what they do. Always testing. Dog eat dog world. Strongest survive……goes on & on….lol
A 6 year old wolf is an old bush warrior probably eking out survival by himself pushed out by his younger brethren of family members.

"a classic couple"

Whacked her sister in order to take her sister's husband and kids. Yup, classic.

Park Service study showed the major cause of wolf mortality was……..other wolves!

This. And I read that for most packs within 7 years no original members remain

Great story MJM. Are you a wolf biologist?

No, I am a copy paste type of guy. But that is what most of them are too. They learned it from a book, that a guy wrote with no field time. But he read a book too.

Mark, any idea what Yellowstone's wolf count is at now?

Read somewhere that the wolves in Wy and yellowstone took a big hit from distemper... any truth to that?

One can only hope.

I looked for Yellowstone numbers and found number for 2024 and older. 2024 says 108 in YNP.


He is a write up on Wy Yellowstone.
A flare up of a disease that’s especially lethal to wolf pups took a toll on Wyoming and Yellowstone National Park wolf numbers in 2025, reducing biologists’ counts to a level last seen when wolves were still reestablishing following the species’ historic 1995-96 reintroduction.

“It was the lowest number of wolves in 20 years,” Wyoming Game and Fish Department wolf biologist Ken Mills told WyoFile. “That was definitely during the population creep stage, so they were still establishing in the state.”

All signs point toward canine distemper being the primary reason Wyoming’s statewide wolf population plunged to a minimum count of 253 wolves and 14 breeding pairs at the end of 2025, Mills said.

Distemper was detected in 64% of animals in the northwestern Wyoming zone where wolves are classified as “trophy game.” While adults can survive the contagious virus, which is a measles-like affliction in canines, it’s “quite lethal” for pups and only an estimated “31 to 34” of the 87 documented born pups lived to the end of the year, a survival rate of just 37%, according to Game and Fish’s 2025 wolf monitoring report.


In the past, distemper was a density-dependent disease that surged when populations were high, Mills said. It last flared up in 2018, which wasn’t long after a two-year period where wolves were protected from hunting by the Endangered Species Act and populations — and conflict — were higher.

The 2025 flare up was the first time Mills documented lots of distemper when wolf numbers were not particularly high. The occurrence has him searching for alternative explanations.

“Could it be cyclical? Yeah,” the Pinedale-based biologist said. “However, these are potentially eight-year cycles, and it takes a lot of time to collect data and understand what’s going on.”

There’s cause to believe that distemper will abate in Wyoming wolves this year. When Yellowstone wolves have experienced outbreaks, the event lasts a year and then there’s recovery, Mills said. And the Wyoming population now has more antibodies and resistance built up and so is in good shape to recover itself, he said.


But in 2025, distemper hurt Wyoming wolf numbers, which was a first.

Before that, “we really haven’t had a canine distemper outbreak that has caused a population-level effect,” Mills said.

In 2024, Mills and his biologist counterparts detected 330 wolves and 24 breeding pairs statewide. The estimated 253 wolves and 14 breeding pairs in 2025 means the raw wolf count tumbled by 23% and the reproductive segment fell by 42%.

Of those, 132 wolves in 22 packs that included 10 breeding pairs dwelled in the mountainous portion of northwest Wyoming in the “trophy game” area. There were nine wolves in three packs and no breeding detected on the Wind River Indian Reservation. And in the zone where Wyoming manages wolves as predators — where they can be killed by any means without limit — there were 28 wolves in five packs, including one breeding pair.

The remainder of Wyoming’s wolves — 84 wolves running in seven packs that included three breeding pairs — dwelled in Yellowstone National Park, according to the state’s monitoring report.


The park’s public affairs officers, whose office has been inundated with inquiries about a recent grizzly bear attack, did not respond to WyoFile’s request for an interview before this story published.

The overall number of Yellowstone wolves has dipped into the 80s twice before, in 2012 and 2018. But by other measures, 2025 was a tough year that the park population had not experienced since the reintroduction era. The distemper outbreak appeared to be “synchronous” in Wyoming and Yellowstone, and pup production and survival was also dismal in the national park, Mills said.

“Seventeen pups survived in Yellowstone,” he said, “which was the lowest they ever recorded.”

Outside of Yellowstone, Game and Fish will consider the lower wolf population when its biologists and wardens are setting fall 2026 hunting seasons (hunting isn’t allowed in the park, though park wolves frequently leave ). That proposal isn’t public yet, but Mills anticipates that there will be a “surplus” of animals and a wolf hunting season, even if mortality limits are reduced.


Wyoming’s relatively few wolves have enabled the state to manage with precision and a degree of predictability, although the surge of distemper interrupted a long run of population stability. Still, the unexpected disease outbreak left Mills feeling good about Wyoming’s plan for managing its wolves.

“We set up the population objective of 160 wolves to be able to accommodate an event similar to what we experienced, and still meet our minimum recovery criteria,” Mills said.

That recovery criteria includes 10 breeding pairs outside of Yellowstone in Wyoming’s trophy game area. Mills’ 2025 surveys detected exactly 10 packs with pups in that zone.

“We met the minimum,” Mills said. “It actually worked exactly as we intended"

In Alaska's Denali National Park (where everything is supposed to be Disneyesque and thus perfect...) even the NPS has had to admit that the primary mortality factor on "their" wolves is in fact, other wolves.

And this was despite all the teeth-gnashing and media reports of wolves leaving the park and being killed by hunters and trappers. The incorrect hunter/trapper mortality theory was why the anti's continue to agitate for a "wolf buffer zone" around the park.

Sometimes the "science" just smacks you in the cranium as the politics go out the "Open Window of Reality!"

Pete