Mammals are increasing nocturnal activity to reduce run-ins with humans; this still threatens survival for many species.
At no point of time, perhaps in Earth’s history, has the fate of so many species been so completely at the mercy of just one, as it is now—in the Anthropocene. Climate change, species hunted or felled to extinction, domestication and agriculture, every bit of natural history as it is unfolding today bears humanity’s imprint. Findings of a study published earlier this month in Science says human activity is now causing profound changes in animals’ habits. Mammals around the world are becoming more active at night when there are lesser chances of encountering humans and human activity. Though it is difficult to say what impact this could have, scientists quoted in a Nature article believe that this could put the very survival of several animal populations at an increased risk.
Researchers analysed 76 studies that monitored the activity of 62 mammal species across six continents, comparing night-time activity during periods of time or in regions that saw high human disturbance—hunting season, areas with high road density—with night-time activity during periods of time or in regions that experienced low human disturbance. As per the meta-study, mammals exposed to higher levels of human disturbance have become 20% more active at the night. While game-hunting is legal for some animals in some countries, rapidly expanding human habitation is eating into the habitats of most animals around the world. What is indeed alarming is that relatively less frequent/dense and nearly explicitly harmless human activity, such as hiking, has almost the same effect on the diurnal/nocturnal split as a much more frequent/dense, yet, only moderately explicitly harmful human activity as agriculture. While avoiding humans/human activity reduces animals’ risk of a lethal encounter, it nevertheless has chilling consequences for animals. Most diurnal animals are left evolutionarily handicapped for feeding and mating, and are consequently pushed closer to getting wiped out. For many large predator species, with numbers already dwindling, widespread failure to mate or feed could mean extinction.