Scientists Notice Unusual Movement Among Yellowstone’s Wolves — And Their Pups Were Involved Too

Up until the mid-1990s, the ecosystem of Yellowstone National Park had turned into a gloomy, barren land, overgrazed and overpopulated by elk. But ever since wolves were reintroduced in the park, the ecosystem experienced a dramatic transformation, per National Park Diaries. The life that had been squashed into a dormant state reignited, and the park, once again, was brimming with health and lushness. Just by being present, the wolves shifted the ecosystem’s picture, all the while ripping elk carcasses to feed themselves. Today, these elk don’t even think about prowling near “Valley of Fear,” a steambank dotted with aspens and firs.

Ever since wolves triggered a metamorphosis in the park, biologists have become curious to understand how they live, feed, mate, and prey. In a new study published in the journal Current Biology, they revealed a fascinating observation recorded in gray wolves from game trap cameras they installed in Yellowstone National Park.

These gray wolves carry the strength of Yellowstone within their incredible, enduring bodies, as they roam around the region preying on bison, elk, and other smaller animals. Millions of people who visit Yellowstone often observe these gray wolves around areas like Lamar Valley, Hayden Valley, and Slough Creek. These wolves are born utterly helpless, blind, deaf, and lacking any acute sense of smell that they can use for scent-marking. According to a long-held assumption, these wolves remain spatially anchored to their homesites during the pup-rearing seasons. However, in contrast to this notion, scientists recently noticed something very unusual. 

They set several game trap cameras to observe the “movements” and “evolution” dynamics of these wolves. One camera captured the sight of an adult female mom carrying a squirming pup by its butt, as if telling him, “All right, we’re doing this.” The behavior piqued scientists’ curiosity. At this age, the pup was not supposed to be out of its home, nor was its mom. But the snapshot, along with many others, shattered the previous assumption that wolves don’t migrate unless their pups are old enough. The long-distance migration itself is unsurprising. But these wolves migrating long distances to a rendezvous site were entirely unexpected.

The research was initiated in 2019 when the team captured a game camera image in the Greater Yellowstone Ecosystem. They were investigating the Absaroka Mountains, a rugged landscape slung with meadows and forests. During the summers and winters of 2021, they collected data related to the “movement analysis” from the GPS chips they tucked to the wolves’ collars in partnership with the Wyoming Game and Fish Department. Observation of hundreds of Cody elk herd as well as their wolf predators revealed that wolves were using a movement-based strategy to exploit prey, a long-distance migration tactic, also called “migratory coupling.”

Instead of remaining resident, the wolves were shifting to where the elk population was high in numbers. “So we were investigating wolf kill sites to see what they were killing and eating,” Avery Shawler, from the University of California, Berkeley, in 2024, said in a press release. The research illuminated the scope and the whole picture of how wolves use migratory coupling to track and exploit the partially migratory prey. In particular, the researchers noticed that canids tended to migrate long distances when their prey migrated.

Senior author Arthur Middleton reflected that the research unleashed fresh perspectives about shifting ungulate migrators, predator behaviors, and ecosystem dynamics. He noted that the study is the first time researchers outside the Arctic have observed gray wolves shifting their territorial range to be closer to the prey during pup-rearing season. “It’s sort of become pretty obvious to me that ungulate migrations are really important to the functioning of the ecosystem,” Middleton said. “But, we’ve had work to do to show how and why, and so I think this helps add another piece of that puzzle.”

More on Green Matters

A Feared Yellowstone Predator Is Quietly Restoring the Balance of Nature in a Way No One Expected

Thrilling Footage Shows a Female Wolf’s Surprising Encounter With Tourists at Yellowstone

Scientists Tracked Migrating Bisons in Yellowstone for 6 Years — and Found Something Incredible