The persistent presence of humans and their infrastructure in U.S. national parks has yielded dramatic changes in the behaviors of large animals who live there, a new study has found.

Even during the pandemic-era lockdowns that briefly closed parks to humans in 2020, large animals at most sites continued to avoid human-built roadways and facilities, according to the study, published on Tuesday in the Proceedings of the Royal Society B.

This wasn’t true in all cases, as animals in more developed areas did switch from avoiding human infrastructure in 2019 to using it more in 2020, per the study. But across all parks and species — particularly in remote areas — the avoidance behavior generally persisted.

“Wildlife all around the world fear people and avoid areas of high human activity,” lead author Kaitlyn Gaynor, a zoologist at the University of British Columbia, said in a statement.

“But it was surprising to see that this holds true even in more remote protected areas,” Gaynor added.

To understand these behaviors, the researchers evaluated GPS collar data for 229 animals from 10 species across 14 national parks and protected areas, from 2019 to 2020.

Using this range of dates, they explained, allowed for an assessment as to how animals navigated human activity hubs in parks both before and during what they described as a COVID “Anthropause” — a time with far fewer human visitors.

The species of interest included grey wolves, mountain lions, black and grizzly bears, moose, mountain goats and bighorn sheep.

Overall, the researchers found that animals tended to avoid infrastructure like roads, trails, parking lots, buildings and campgrounds, although these inclinations varied among populations, species and individuals.

For example, animals located in more developed areas were more willing to explore those places without any people around in 2020, according to the study.

Managers at Yosemite, for example, told the researchers that even after people came back following pandemic-era closures, the black bears stuck around — causing problems.

“The bears got used to the abundant food in Yosemite Valley and didn’t want to give it up,” Gaynor said.

But although some populations, like the Yosemite black bears, showed a robust response to park shutdowns, she stressed that “most did not.”

“Because a lot of headlines in 2020 implied that animals were taking back our national parks and were on the streets everywhere, we expected to see a bigger effect,” Gaynor said. “But it takes just a few individuals to start changing their behavior to create the perception of a larger impact.”

The researchers also hypothesized that due to the relatively short length of the pandemic closures — which on average lasted about 58 days — many animals may have lacked the time necessary to perceive and react to shifts in human activity.

They also speculated that risk-averse animals may have already been displaced before the pandemic began — meaning that those with greater exposure to humans may have already been habituated to their presence.

Addressing these differences in response, co-author Forest Hayes, a postdoctoral fellow at Colorado State University, noted “the complex ways that animals balance risks and benefits associated with humans.”

Echoing these sentiments, Gaynor said that “some species are just more wary of people than others, like bighorn sheep and mountain lions, while others have learned to associate humans with some benefit.”

For example, she explained, mule deer and elk at Zion National Park tend to linger around humans in developed areas, possibly as a way of avoiding their predators.

Emphasizing the varying responses of animals to human presence, the authors noted the conflicting but coexisting interests of park recreation and conservation activities.

These responses, they added, can shape how species compete — prompting changes in ecosystem dynamics and affecting how animals persist alongside people.

“This study provides evidence that conservation is compatible with recreation at low levels but that we do need to keep some areas exclusively for wildlife,” Gaynor said.