Study published in Science demonstrates that animals respond quickly to human behavioral changes

Human behavior changed dramatically during lockdowns in the first months of the global COVID-19 pandemic, resulting in behavioral changes of land mammals. This is according to a study published in Science (DOI: 10.1126/science.abo6499) by a large international research team led by Prof. Marlee Tucker, an ecologist at Radboud University in the Netherlands, in which Prof. Justin Calabrese, a scientist from the Center for Advanced Systems Understanding (CASUS) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), was also involved. Wild mammals traveled up to 73 percent longer distances on average and occurred 36 percent closer to roads during strict lockdowns.

Tucker and 174 colleagues analyzed global data from land mammals tracked by GPS devices. “There were many media reports that nature was recovering during those first lockdowns. For example, cougars were roaming the streets of Santiago, Chile, but we wanted to know: is there any evidence of this? Or were people simply paying more attention to everything while being at home?”, asks Tucker. Co-author Calabrese has been conducting research at the interface of ecology and data science at the HZDR institute CASUS since 2020. He explains: “There is very rarely an opportunity to track how animals adapt their movement patterns in response to a change in human behavior, achieved in the form of a natural experiment on a global scale, using so many mammal species.” This was a unique opportunity, he concludes, because the world virtually stood still during the first phase of the pandemic: “Thanks to the global network of scientists, it was possible to observe and evaluate the reactions of the animal kingdom.”

Movements of mammals

Tucker and colleagues collated data from the movements of 43 different species of land mammals from around the world. In total, more than 2,300 individuals were included: from elephants and giraffes to bears and deer. The researchers compared the mammals’ movements during the first period of lockdowns, from January to mid-May 2020, with movements during the same months a year earlier. “We saw that during strict lockdowns, animals traveled up to 73 percent longer distances in a period of 10 days than the year before, when there were no lockdowns. We also saw that animals occurred on average 36 percent closer to roads than the year before. This is probably because those roads were quieter during strict lockdowns,” outlines Tucker.

There are several explanations for these results: there were fewer people outside during strict lockdowns, giving animals the opportunity to explore new areas. “In contrast, in areas with less strict lockdowns, we saw that animals traveled shorter distances. This may have to do with the fact that during those lockdowns, people were actually encouraged to go into nature. As a result, some nature areas were busier than before COVID-19,” says Prof. Thomas Müller, Senckenberg Biodiversity and Climate Research Centre and Goethe University Frankfurt, who designed the study together with Tucker.

Unique opportunity

The “anthropause” provided a unique opportunity to study the effects of an abrupt change in human presence on wildlife. “We succeeded in showing evidence-based that mammalian species worldwide changed their behavior during the pandemic,” says Calabrese. “This offers hope for the future, because in principle this means that making some adjustments to our own behavior could have a positive effect on animals,” Tucker concludes.


Marlee A. Tucker, […] Justin M. Calabrese et al.: Behavioral responses of terrestrial mammals to COVID-19 lockdowns, Science (2023), DOI: 10.1126/science.abo6499 

About the Center for Advanced Systems Understanding

CASUS was founded 2019 in Görlitz/Germany and pursues data-intensive interdisciplinary systems research in such diverse disciplines as earth systems research, systems biology or materials research. The goal of CASUS is to create digital images of complex systems of unprecedented fidelity to reality with innovative methods from mathematics, theoretical systems research, simulations as well as data and computer science to give answers to urgent societal questions. The founding partners of CASUS are the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Helmholtz Centre for Environmental Research in Leipzig (UFZ), the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden (MPI-CBG), the Technical University of Dresden (TUD) and the University of Wrocław (UWr). CASUS, managed as an institute of the HZDR, is funded by the German Federal Ministry of Education and Research (BMBF) and the Saxon State Ministry for Science, Culture and Tourism (SMWK).