The Mere Presence of Humans—Not Just Our Changes to the Land—Can Alter Wild Animals’ Behaviors, a New Study Suggests

Researchers examined GPS tracking data from thousands of animals representing 37 species and anonymized cellphone location data from 2020, a year of Covid-19 lockdowns, and the previous year

Sarah Kuta | Daily Correspondent

May 26, 2026 10:00 a.m.

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The world is in the throes of a biodiversity crisis, with numerous animal species declining or disappearing altogether. Scientists know that much of this turmoil stems from human development—physical changes to the landscape such as the construction of roads and the felling of forests.

But how much is the mere presence of humans affecting wild animals? A lot, new research suggests.

A new study, published May 21 in the journal Science, that relied on tracking data before and during Covid-19 lockdowns, found that human activity changed how most of the 37 analyzed wild animal species interacted with their surroundings. The presence of humans seemed to cause some species to cover a wider geographic area and occupy broader environmental niches, while at the same time causing other species to shrink their range and narrow their habitats.

Scientists are still trying to tease out the implications of these findings. “Is this evidence of them successfully adapting to us, or is this evidence of [humans putting] pressure on them?” study co-author Ruth Oliver, an ecologist at the University of California, Santa Barbara, tells the New York Times’ Emily Anthes.

But overall, the study suggests scientists must consider both physical changes to the land and the presence of people when evaluating the effects of human development on wildlife. “We really can’t understand the full picture without information on both of these factors,” Oliver adds.

The paper is the latest research to come out of the Covid-19 Bio-Logging Initiative, a international effort to study how the pandemic lockdowns of 2020—a period of limited human mobility dubbed the “anthropause”—affected wildlife. Past research found that animals traveled longer distances and seemed to act more relaxed in the absence of people and vehicles.

For the new study, Oliver and her colleagues compared GPS tracking data from more than 4,500 individual animals representing 22 bird species and 15 mammal species with anonymized cellphone location data in the United States. They examined movement from January through August in 2019 and 2020.

With the GPS tracking data, they looked at the size of the geographic area each creature covered each week, as well as the range of different habitats they occupied. With the cellphone location data, they estimated how many people were physically present in census blocks across the country each week.

“The cellphone data we used was made available to researchers during the pandemic to help reveal the impacts of Covid-19 shutdowns,” says study co-author Scott Yanco, a research ecologist at the Smithsonian’s National Zoo and Conservation Biology Institute, in a statement. “Typically, these data are difficult or expensive to access, which made this a rare opportunity for us to quantify how human presence impacts wildlife, and to demonstrate that there is more to consider than just land modification to create robust conservation plans.”

During the pandemic lockdowns, about two-thirds of the species included in the study changed the size of the area they occupied or the scope of their environmental niche, the data revealed.

But the presence—or absence—of humans affected species very differently, the researchers found. For example, when humans were present, common ravens expanded their range by ten square miles per week per animal, but coyotes shrank theirs by roughly four square miles. Similarly, the presence of humans caused common ravens to narrow their interactions with habitats and resources by an estimated 46 percent, while causing cougars to broaden theirs by 10 percent.

The effects of human presence also varied depending on how much humans had already altered the landscape. The impacts were larger in more natural environments, like national parks, and smaller in more heavily developed areas, like cities. The scientists suspect that creatures living in undeveloped places might be more sensitive to human presence, or that animals in more developed locations have already minimized their space use, per the Times.

“Habitat loss is the key driver of biodiversity loss, but as we show, human’s direct use of the landscape—say for recreation—also mediates this effect,” study co-author Walter Jetz, an ecologist at Yale University, says in a separate statement. “Depending on the quality of remaining habitat, animals make behavioral adjustments that either amplify or dampen the negative effects of habitat loss.”

But what does all this mean for wild animals? Are these human-caused behavioral changes good or bad? Scientists aren’t sure, but they hope future studies will shed light on these and other questions.

In the meantime, the findings indicate conservationists must consider both habitat modification and human behavior if they hope to protect wildlife. The evidence also seems to provide support for short-term restrictions on human activity, such as the temporary closures of rock-climbing routes during raptor nesting season and trails when elk are migrating and calving.

“Because humans induce fear in many animals, even nonlethal human activity can have negative impacts on wildlife,” writes Lydia Beaudrot, an ecologist at Michigan State University who was not involved with the research, in an accompanying commentary on the paper. “Understanding how and why wild animals respond to the presence of people can guide actions to minimize the impact of human activity.”

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.