Deer Learn To Ignore Deterrents: Human shouts scare best; habituation soon blunts effect

What scares a deer away from a crop field, a wolf howl, a cougar call or the sound of a human shouting? A 2025 study by researchers from the University of Alberta and King’s University found that, among the sounds tested, human shouts produced the strongest flight response in both deer and elk. But the effect did not last: over six weeks, both species became increasingly accustomed to the stationary deterrents. The study, published in Ecology and Evolution, tested audio and flashing-light deterrents on agricultural fields in British Columbia’s Cowichan Valley, where Roosevelt elk and black-tailed deer frequently enter crop fields and can damage crops and fences.Human shouting worked better than predator callsBetween August 4 and September 17, 2023, researchers placed motion-activated devices on 15 crop fields. When an animal approached, the devices played one of several sounds: people talking, people shouting, wolf and cougar vocalisations, dog barks or local bird calls. Some trials also included flashing LED lights.The researchers analysed 680 usable encounters involving elk and deer. The difference between ordinary human speech and shouting was particularly striking. Deer fled in...