For thousands of years, human activity has reshaped natural landscapes. Cities, farms, highways and settlements have forced wildlife to adapt to environments increasingly dominated by people. New research suggests that this is only part of the story.

Animals may also change their behavior simply because humans are physically nearby, even when the surrounding landscape itself has not changed.

A large study combining animal GPS tracking with anonymized cellphone-location data found that wildlife responses to humans vary dramatically between species and environments.

The key finding is that animals react not just to what people build, but also to where people actually are.рог

A Rare Natural Experiment

The COVID-19 pandemic created an unusual opportunity for scientists.

Lockdowns dramatically changed where people traveled, how often they moved and which places they visited. Researchers compared wildlife movement during matching periods in 2019 and 2020, using GPS records from 4,581 individual mammals and birds representing 37 species across the continental United States. Tracking the animals was relatively straightforward. Tracking humans was more difficult. Most wildlife studies estimate human pressure indirectly by looking at things such as roads, agriculture, buildings or population density.

Those measurements reveal how landscapes have been modified, but they do not show exactly where people are moving at a given moment. To solve this, the team used anonymized cellphone geolocation information with neighborhood-level detail. That allowed researchers to separate permanent landscape changes from the immediate physical presence of people.

Human Presence Changes Behavior

The study examined both the territory animals used and their environmental niche, meaning the types of habitats and resources they occupied. For most species, landscape modification alone could not explain the observed behavior. Human presence mattered too. Around 57% of the species studied were influenced by both factors.

Human activity was associated with changes in space use or environmental niches for roughly two-thirds of both mammal and bird species.

Wild Areas Can Be More Sensitive

One of the most interesting patterns appeared in less-developed landscapes.

Animals were often more sensitive to human presence in places such as national parks than in heavily modified urban environments. About two-thirds of mammal species and around 41% of bird species reduced the amount of habitat they used when human presence and landscape alteration occurred together.

That suggests animals living in relatively natural areas may respond strongly even to temporary increases in visitors.

Different Species, Different Reactions

There was no single response shared by all wildlife. Wolves, for example, expanded their habitat use when people were present. Researchers suggest this may reflect their long history of conflict with humans, with animals spreading out or traveling farther to avoid human activity.

White-tailed deer behaved differently. Their environmental niche expanded in more heavily modified landscapes but became smaller when human presence increased. Sandhill cranes showed almost the opposite pattern. The contrasting responses highlight why wildlife management cannot rely on one universal strategy.

Each species has different needs, tolerances and behavioral patterns.

Lessons From the Anthropause

The study is part of a broader international research effort examining wildlife during the pandemic period sometimes called the “anthropause.” That project brought together hundreds of researchers and compiled around one billion location records from approximately 13,000 animals.

Earlier work has already shown major changes in mammal movement and marine traffic during lockdown periods. The latest results add another important piece by showing how direct measurements of human movement can improve understanding of wildlife behavior.

Stress or Adaptation?

One major question remains unanswered. If an animal changes where it travels or which habitats it uses because people are nearby, is that adjustment helping it survive, or is it evidence of stress? Researchers are now examining whether animals that change their behavior in response to human pressure face higher or lower risks of death.

That distinction will be critical. A behavioral shift may look like successful adaptation while actually forcing animals into poorer habitat or using more energy.

Better Conservation Decisions

The research suggests future conservation plans could become more precise by combining information about infrastructure with real-time patterns of human activity.

Instead of simply declaring an entire area protected, managers could consider when and where animals most need space from people.