Camera traps, which automatically capture images of wild animals when they detect movement and body heat, have become major research tools for wildlife biologists. The new study is based on data from 102 different camera fit projects in 21 countries. (Most were centered in North America or Europe, but South America, Africa, and Asia were also included.) The data allowed scientists to study the activity patterns of 163 different species of land mammals, and track how often humans appear even in the same locations.
“One of the primary strengths of this paper is that you get information about both humans and animals,” Marlee Tucker said. An ecologist at Radboud University in the Netherlands, he was not involved in the new research.
During the pandemic lockdown, human activity decreased in some project sites while increasing in others. At each study site, the researchers compared the number of times wild animals were detected during a period of high human activity and a period of low human activity, regardless of whether the decrease in activity came during the closure period.
Carnivores, such as wolves and lynxes, appear to be very sensitive to humans, showing the greatest declines in activity when human activity increases. “Carnivores, especially large ones, have a long history of hostility with humans,” Dr. Burton said. “The consequences of carnivores colliding with people or getting too close to them often means death.”
On the other hand, the activity of large herbivores, such as deer and moose, increased when humans were outside. This may be because the animals simply have to move more to avoid crowds of people. But if people help keep carnivores away, it could also make it safer for herbivores to come out and play.
“Herbivores tend to be less fearful of people, and may actually use them as a shield from carnivores,” said Dr. Tucker, who praised the study authors for being able to “unpack all these different human influences.”
