Lead author, Liana Zanette, sets up the camera trap and speaker system in South Africa's Greater Kruger National Park. Credit: Current Biology, Zanette et al.
Key points:
- Mammals living in South Africa’s Greater Kruger National Park are more afraid of human voices than lion vocalizations or hunting sounds.
- Animals were twice as likely to abandon waterholes in response to hearing humans.
- Human voice sounds can be used to intentionally steer endangered species away from dangerous poaching regions.
New research, recently published in Current Biology, reveals that mammals living in South Africa’s Greater Kruger National Park fear human voices more than lion vocalizations or hunting sounds.
“We usually think about the top of the food chain being large carnivore predators,” said study author Liana Zanette, a conservation biologist at Western University. “But what we’re interested in is the unique ecology of humans as predators in the system, because humans are super lethal.”
Using a custom waterproof camera and speaker system positioned at waterholes during the dry season, researchers observed the behavior and reactions of 19 mammal species in response to a series of recordings, including human voices, lion vocalizations, barking dogs, and gunshots. The human voice clips were at a conversational volume and sourced from radio or television recordings of people speaking the four most used languages in the region – Tsonga, Northern Sotho, English, and Afrikaans. The dogs and gunshots represented the sounds associated with hunting, while the lion vocalizations signaled the presence of the top predator in the area. By the end of the experiment, the team had 15,000 videos to sift through.
Animals were twice as likely to flee the waterholes upon hearing humans compared to hearing lions or hunting sounds. Ninety-five percent of the animals, including giraffes, leopards, zebras, kudu, warthog, impala, elephants, and rhinoceroses, ran more often or abandoned waterholes faster in response to humans compared with lions. Despite the belief that animals habituate to humans if they’re not hunted, these results indicate that the fear of humans is both ingrained and pervasive for animals in Greater Kruger National Park.
Currently, the research team is investigating if their custom sound system can be utilized to steer endangered species away from poaching sites. In fact, using human voice recordings to keep the Southern white rhino away from certain areas has been successful.
“I think the pervasiveness of the fear throughout the savannah mammal community is a real testament to the environmental impact that humans have,” explained Zanette. “Just having us out there on that landscape is enough of a danger signal that they respond really strongly. They are scared to death of humans, way more than any other predator.”