WOLF CONSERVATION RESEARCH SUPPORTED BY YELLOWSTONE FOREVER REVEALS THE IMPORTANCE OF 907F AND OTHER ELDERLY WOLVES
Wolf 907F is a living legend. Resilience born of tooth and flesh. Defying expectations and averages, the 11-year-old alpha female is the oldest known wolf in Yellowstone National Park, and has led one of the park's longest established packs for nearly a decade.
With shaggy gray fur and a missing left eye, the wolf known as 907F has blown scientists away not only by living long past her life expectancy, but by continuing to be healthy enough to lead the pack and reproduce annually. For 10 consecutive years she has raised pups, led hunts, and fought rivals, and though she temporarily lost her leadership to a newcomer, she was later restored as guardian of the Junction Butte pack — one of the largest in Yellowstone.
Now nearly 11-and-a-half years old (11.5 to be exact), 907F has blasted past wolves’ average life expectancy of 3 to 4 years, and entered a category shared by very few.
“According to the information that we have starting in 1995 with Wolf Reintroduction, she is the fifth oldest [wolf] that we have ever recorded during that 30 years,” explains Kira Cassidy. Cassidy is a research associate at the Yellowstone Wolf Project, one of the world’s longest running and most detailed studies of large carnivores. The research is made possible by the efforts of Yellowstone Forever, the park’s official nonprofit partner and an organization that Jacques Marie Mage has worked closely with to support this and other research projects.
“She is currently the oldest alive in the park,” continues Cassidy, “the oldest one ever in Yellowstone hit 12-and-a-half and so she would have to live quite a bit longer to be the oldest ever in Yellowstone. Of those five that have hit 11… she is the only one that has lived in a place in Yellowstone where people can actually see them.”
Cassidy has been monitoring 907F since the wolf was a pup. According to Cassidy, who spoke about the wolf recently on Episode 191 of Wolf Connection, 907F has been captured, collared, and handled three different times – the first was when she was 9 months old, the last when she was 7 and fitted with a new radio collar.
She's been the leader of her pack since she was three — a role she inherited from her aunt, who died. "She is one of probably only a few wolves that never had to disperse and leave her home territory to start a new pack," Cassidy said in an interview with CBC.ca. "That helps quite a lot. She didn't have to go through that alone period, trying to find a new place to live."
Her pack currently has 11 adult wolves and five pups — two of them are hers, and three are her grand-pups — which is about average. But it has, at various points, been particularly populous. In 2020, her pack reached a peak of 35 members.
Having that many pack mates lowers 907F's chances of getting killed by a wolf from another pack, which Cassidy says is the number one cause of mortality for Yellowstone wolves. But the size of the Junction Butte pack has as much to do with 907F’s success as 907F’s success has to do with the health of the pack.
According to a 2023 study titled, “Human‐caused mortality triggers pack instability in gray wolves,” Cassidy and her co-authors note “that even the loss of a single wolf, especially a leader, can have detrimental effects on the pack.” And the death of a pack leader even more so: “The human-caused mortality of a pack leader decreased the predicted odds of pack persistence to the end of the biological year by 73% (1: 0.27) and reproduction the following year by 49% (1: 0.51). These results indicate that human activities can have major negative effects on the biological processes of wildlife that use protected areas.”
In other words, 907F’s ability to avoid being killed by humans and wolves has provided a relatively unbroken chain of leadership that has allowed for pack growth and stability, which in return provides the conditions for their leader to thrive.
And thrive she has. Last Spring, 907F welcomed her 10th litter, a sign that “she has enough fat and she is strong enough to lactate and provide the milk," said Cassidy. "So overall, it seems like she's still very healthy."
Her new pups join a multi-generational pack consisting of 907F’s grown adult children and grandchildren. A proper matriarch with deep and detailed knowledge of her territory–from the best places to cross a river to how to avoid humans, for example– 907F is a font of wild wisdom that lends itself to the Junction Butte pack’s longevity, providing the lived experiences that can be so vital in the continued fight for survival.
