Human activity has caused a lot of changes to wildlife, to the point that some animals have even evolved faster to adapt to humans. Researchers find that many mammals worldwide have become more nocturnal to avoid humans.

Mammals Turning Nocturnal

A new study published in the journal Science finds that mammals worldwide are shifting their behavior to become more nocturnal in response to human activity. Researchers analyzed 76 papers that studied 62 animal species in six continents, including otters in Brazil, tigers in Nepal, coyotes in California, and wild boars in Poland, and they also compared how much time the animals were active at night when faced with various human disturbances such as hiking, farming, and hunting.

Interestingly, researchers found that on average, mammals are 20 percent more active at night when faced with human activity, even if the animal is not naturally nocturnal in nature. The pattern was found to be consistent across continents, taxa, human activity, and habitats. This is perhaps because there is generally less human activity at night, so the animals are less likely to encounter humans at that time of day.

“Animals responded strongly to all types of human disturbance, regardless of whether people actually posed a direct threat, suggesting that our presence alone is enough to disrupt their natural patterns of behavior,” said Kaitlyn Gaynor of the University of California, Berkeley, study lead.

Wildlife Adapting To Humans

The results of the study show that humans have a direct impact on wildlife even if they are not deliberately trying to do so. In places such as Africa, human-animal relationships are more pronounced, with human populations continually encroaching on animal population. But in big cities where human populations are more condensed, however, the relationship is less obvious.

Apart from the obvious changes in the habitats of wildlife in cities, everyday human activity can actually change animal behavior, or even the animal itself. For instance, in response to the great number of bird feeders in the UK, the Great Tits of Britain have actually evolved to have longer beaks in just a few decades, while ticks and other bugs in cities have slowly evolved to become more immune to the chemicals in insecticides.

In the case of the current study, the results reveal how human activity, whether actively harmful to wildlife or not, does have a significant effect on wildlife, so much so that animals all over the world have adjusted to being more nocturnal just so they can go about with their business without the threat of human disturbance.

As such, perhaps it’s time to become more careful with activities, and to engage in mindful urbanization wherein both humans and wildlife may thrive without stepping on each other's toes.

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