The more humans have flourished, the more the biggest animals have not. We have always hunted large mammals, downsizing the fauna of whatever continent we happen to visit. Mammoths, woolly rhinos, ground sloths—all gone. In slaying these giants, we have remade the world in ways that we are only starting to appreciate. We have, for example, made it easier for fear to sculpt the land.
Predators instill fear in their prey. Even without actually killing anything, their mere presence creates a state of simmering stress and unease. This anxiety influences how predators’ targets take stock of the landscape around them. Open areas, with long lines of sight and plentiful paths down which to flee, offer safety. Overgrown areas, with obscuring foliage and tripping obstacles, are dangerous. Ecologists call this the “landscape of fear”—a psychological map that prey rely on to assess the risks of their surroundings.
The landscape of fear also shapes these surroundings. Scared prey spend more time in safe zones and less time in risky ones, which in turn affects where plants get eaten, and where nutrient-rich dung gets dropped.
Elizabeth le Roux from Nelson Mandela University demonstrated this pattern through a simple experiment in South Africa’s Hluhluwe-iMfolozi Park. The major predators there, like lions and leopards, are ambush hunters that launch attacks from cover, so le Roux’s team created safe zones by removing that cover. With machetes and mowers, they chopped down trees and trimmed long grass from eight plots of land, while leaving eight similar plots untouched. They then set up motion-triggered camera traps and waited for two years, to see which species would arrive, eat, and defecate.