Wild animals have to adapt to living near human activities like houses, roads, and farms. Scientists say many animals are becoming more active at night to avoid humans.
A study, published in February in the journal Global Ecology and Conservation, looked at how animals change their behavior near humans. Researchers from the University of Manchester in the U.K. and the Ecology and Conservation Laboratory (Laec) at the University of São Paulo in Brazil worked together on the project. They started studying the area in northeast São Paulo in 2013-14, where camera traps were set up.
The area was originally covered by the Cerrado biome but has changed over the years due to farming. Coffee was grown there in the 18th and 19th centuries, then livestock farming, and now there are sugar cane fields and forests of pine and eucalyptus. Adriano Chiarello from Laec, who led the study, says these animals have been living near people for a long time.
Small cameras, called camera traps, were set up in various areas with different levels of protection. These included private properties and protected areas like the Jataà Ecological Station.
“We set up the cameras in different landscapes,” Chiarello explains. “One area had a big protected zone, another had mostly forests with a small bit of trees, and the third had a mix of forests, sugar cane fields, and protected zones.”
Years ago, the photos taken led to a bunch of scientific articles showing where animals lived and what features made those places more or less appealing to them. But in the latest study, the goal was to figure out how humans being around affects animals’ behavior.
“Sometimes, animals still live in an area where there are human things like dirt roads or sugar cane fields, but they’re not active when there’s more chance of running into people,” the researcher says.
The goal was to see how active animals are in different places, comparing areas with more or less protection and how close they are to humans, dogs, and homes.
Out of the six mammal species studied — jaguar, ocelot, giant anteater, brown brocket deer, agouti, and crab-eating fox — five changed their behavior in areas with less protection or closer to humans. Four of these species living near humans became more active at night.
In their usual habitat, pumas are active all day long, but in areas where humans live, they now mostly move around at night, between 6 p.m. and 6 a.m. Agoutis, usually active during the day, now only move around early in the morning.
“Agoutis need to be active early because later there will be people and cars around, which makes them uncomfortable. So, they limit their time out during the day, which affects their role in the environment,” explains Chiarello.
Giant anteaters, which eat termites and ants, are forced to be more active at night because of dogs. In rural areas, many dogs are loose and chase or even hunt wild animals during the day when they are most active.
Chain reaction
The study’s results confirm what other researchers, like Professor Maria João Ramos Pereira and her team from the Federal University of Rio Grande do Sul, have observed. Originally from Portugal and now in Brazil, they have been studying how mammals behave in areas where humans are present, like the Atlantic Forest and the Pampa biome in Rio Grande do Sul.
“Unfortunately, we have noticed these changes in behavior, which can vary from species to species. Not all animals react the same way,” Pereira explains.
Some animals might actually do better with humans around. Take the crab-eating fox, for example. The study mentioned in Global Ecology and Conservation shows that these foxes are seen more often in areas where people live than in untouched areas. Researchers think it’s because they eat just about anything and can find more food in these places.
For other species, it’s more about adjusting their behavior. Pereira and her team looked at how pampas foxes avoid getting attacked by dogs. They found that these foxes still use the same areas but not always at the same time. “It’s like if we both share the same apartment but take turns being active. I might be active today, and you might be active tomorrow,” Pereira explains.
In many cases, when native plants are destroyed and humans move in, animals’ space and time to roam around get limited, but we’re still not sure what the long-term effects of this are.
“It’s like when a family has less money to spend; they struggle to get by. Animals have to find a way to adapt. For example, I can’t go out all day anymore, only in the evenings. Life becomes harder, and when they’re stressed like this, they reproduce less and live shorter lives,” Chiarello explains. “There are some ways animals can cope, but if things get too tough, they might die out, and that’s already happening,” Pereira says.
This forced change not only affects the animals themselves, who have to adjust their habits, but also the whole environment. “Most species play important roles in their ecosystems. For example, agoutis help spread seeds, which helps plants grow,” says Ewart.
“What’s happening sets off a chain reaction that could affect not just those species, but the whole system. Ecosystems are complex networks where everything is connected,” Pereira agrees.
For the researchers, the study’s results show how crucial it is to establish protected areas and follow environmental regulations, like the Forest Code, especially regarding areas like riverbanks and legal reserves on private land. “Because even a small patch of forest can be a safe haven for these animals,” Chiarello explains. “Protected areas really do help safeguard species, their natural behaviors, and their populations,” Ewart adds.
