Forced to work night shift

WILD MAMMALS are switching over to a more nocturnal schedule in response to human activity, says a study published in Science. Researchers reviewed the activity of 62 mammal species in six continents and found that they are 1.36 times more active during the night, compared to their counterparts who live in areas with low or no human disturbance. For instance, grizzly bears in Canada are becoming more active at night in response to hikers, while leopards and tigers in Nepal are doing the same because of increased human foraging and firewood collection in their habitat during the day. "They become nocturnal not just to avoid people but also to raid crops and prey on livestock," says one of the researchers, Justin Brashares, who teaches ecology at the University of California at Berkeley. More research needs to be done to understand how their behavioural changes are affecting them and the ecosystem.