Moving long distances with vulnerable young pups in tow can be risky business for wolves, but a new study indicates some packs in the Greater Yellowstone Ecosystem (GYE) are willing to take their chances to keep tabs on their main food source: elk.

The study, titled “Wolves Use Diverse Tactics to Track Partially Migratory Prey,” published in Current Biology in August 2025, documents lead researcher Avery Shawler’s PhD research through the University of California, Berkeley. In partnership with Wyoming Game and Fish Department (WGFD) biologists, Shawler conducted six seasons of fieldwork studying the movements of elk herds and wolf packs living in the eastern GYE between Yellowstone National Park and Cody, Wyoming.

Originally Shawler set out to document wolf predation patterns. But with the abundant elk and wolf GPS collar data collected, she was able to draw additional conclusions about how wolves moved seasonally.

“Even without GPS collar data [WGFD] knew that some wolves were making long-distance movements,” Shawler said, adding, “Having the GPS collar data, we were able to get more insight into how it coincides with the timing of elk migration.”

Along with her field crew, Shawler collared 99 elk in January and February of 2019 and 2020 and collared a total of 19 wolves that overlapped the Cody elk herd from 2019 to 2021.

Elk typically migrate to the high country in the spring, but changing environmental conditions related to vegetation and snow cover, as well as human development impacts, have caused elk migration patterns to become less consistent with historical observations.

“It’s more on a continuum than migrate or not migrate,” Shawler said.

Some years a wolf pack will migrate, some years they won’t. Packs right next to each other will employ vastly different strategies. These shifts in turn influence the way wolves interact with their prey.

Some of the early research in predator-prey “migratory coupling” as the phenomena is called, linked gray wolf movements strongly to caribou migration in the Arctic. However, the caribou migration is much more consistent than the Cody elk migration.

Outside the Arctic, most wolves were thought to be relatively nonmigratory and that young pups further deter movement, acting as “spatial anchors.”

Combining the GPS collar data with trail camera images, Shawler and others observed packs moving very young pups both short and long distances, up to nearly 24 kilometers, finding that some packs relocate pups to different den sites along elk migration routes, or throughout different parts of elk summer range. These findings challenge the general belief that migrating elk escape predation because wolves are typically tied down to den sites in the spring.

Shawler identified three tactics that wolves used in the study area: (1) “resident,” those that stayed in an area, (2) “migratory,” those that moved with prey and (3) “commuter,” those that mixed tactics. One unanticipated finding in Shawler’s research was that packs often changed tactics year to year, depending on prey densities.

The study also identified reasons why wolves with pups might choose to stay put at their original den sites, regardless of whether elk migrate out of the area. First, newer packs or packs with high member turnover tended to stay resident. Second, areas with high wolf densities were less likely to migrate, possibly because they needed to occupy or defend territories rather than move. And third, the availability of alternate prey such as deer, pronghorns and cattle also decreased the instances of wolves following migratory elk.

For Ken Mills, WGFD wolf biologist and a co-author on the study, the research quantified the connection between predator and prey movements he had been seeing for more than a decade.

“The packs that [Shawler] was looking at were all neighbors and were doing different things based on the different circumstances, and that’s really adapting to what the prey are doing.”

Mills says that the data from Shawler’s study confirm the viability of WGFD’s current management plan. For example, Wyoming wolf hunt areas are drawn to accommodate its packs with more consistent migratory behaviors year to year. “If you can maintain a social structure in those packs’ dynamics and pack behaviors year to year, you’re going to see a lot of the same behaviors, so our management approach is conducive to keeping the status quo year to year,” Mills said.

But the management implications for wolves and elk don’t stop at the Cowboy State’s lines.  Because the research took place in Wyoming’s “Wolf Trophy Zone,” where wolf hunting is regulated, Shawler sees part of the importance of the study as a shift to monitoring wolves in more complex ecosystems. She says much of the body of wolf research has been conducted in protected lands such as Yellowstone National Park. But that doesn’t reflect the status of most wolf populations in the West today.

“There are now more wolves outside of protected areas than in protected areas in the West,” Shawler said, stressing the importance of “learning how to manage them in areas where they are coming into contact with people and in areas where the prey population might not be as robust as in the core of Yellowstone.”

Part of Shawler’s research also examined how ranchers adapt to living with wolves. Her interviews found that the trust between WGFD and the ranching community is essential to mitigating wolf-livestock conflict and social tension associated with it.

Shawler’s advisor, Arthur Middleton, a University of California, Berkeley, professor, co-hosted a symposium in 2016 with Western Landowners Alliance to understand the research needs of landowners in the area, and Shawler’s study helped build upon that.

“It was in recognition that if we are going to be doing research on wildlife in places where working landscapes and ranchers play a huge part in stewarding wildlife, then we should make sure we are working closely with these people and take their needs into account,” Shawler said.

Overall, Shawler’s research adds to the conversation and understanding of predator-prey dynamics in evolving ecosystems, and the challenges when managing landscapes where wildlife and people interact.