Topline
Humans pose a greater threat to mammals in South Africa than any other predator—including lions—which research shows may greatly affect population density, the animals’ ability to feed and potentially cause higher rates of PTSD.
A lion looks out from its enclosure at Sydney Zoo.
Key Facts
Mammals in South Africa’s Great Kruger National Park are much more afraid of human voices than lion noises or hunting sounds, like gunshots or barking dogs, according to a study published Thursday in Current Biology.
The researchers found animals are twice as likely to run away and abandon their waterholes at the sound of human voices over the sound of lions or huntings, and 95% of the species studied ran away more often or abandoned waterholes faster in response to humans than in response to lions.
Lions have long been considered the top predators, or the “kings of the jungle,” so the mammals’ reactions to human sounds might be evidence that humans are “super predators,” according to the study.
Though they were growling and snarling, the lion recordings simulated lion conversations, similar to the human voice clips, which were conversational pieces from radio or television shows in English, Tsonga, Afrikaans and Northern Sotho, the most popular languages spoken in the region.
The researchers looked at the reactions of 19 different mammals, including elephants, lions, buffalos, hippopotamuses, giraffes, hyenas, zebras, leopards and warthogs.
Elephants, rhinoceroses, hyenas, impalas, warthogs and kudus were the species that responded the most fearfully to humans compared to lions.
Crucial Quote
“I think the pervasiveness of the fear throughout the Savannah mammal community is a real testament to the environmental impact that humans have,” first author Liana Y. Zanette said in a statement. “They are scared to death of humans, way more than any other predator.”
Key Background
There’s a growing body of research that supports the claim that wildlife worldwide fears humans as “super predators.” Fear of humans in mesocarnivores—small to medium sized carnivores—greatly outweighs the fear of large carnivores, which is globally “more lethal” and frightening, according to a 2016 study published in Behavioral Ecology. When the sounds of humans were played for badgers, the animals’ ability to feed, forage and stay vigilant was far more negatively affected than when the sounds of dogs, bears and wolves were played. Humans kill prey at greater numbers than any other predator. Human animal collectors prey on more than one third of Earth’s vertebrates and exploit up to 300 times more species than any other predator, according to a June study published in Communications Biology. The study also found that exploitation for medicine, pet trade and other uses affects almost as many species targeted for food consumption and around 40% of exploited species are threatened by human use. Encounters with predators like humans can have significant impacts to the lives of wild animals, according to research published in Annual Review of Ecology, Evolution, and Systematics. When wild birds and mammals hear the sounds of predators for an extended period of time, their populations may significantly decrease, changes in behavior like foraging may be affected and cases of post traumatic stress disorder (PTSD) may increase. The ecological effects of the fear of human predators may also create issues for tourism-dependent conservation, specifically in Africa, the researchers in the Current Biology study report. Less than half of the 186 African protected areas for lions sampled in a 2017 Biological Conservation study were able to support more than 50% of the lions’ prey while less than one third conserved lions at greater than 50% of their estimated carrying capacity. Researchers chalked this up to people settling within the protected areas, the density of humans and livestock in surrounding areas, the size of the protected areas and national economic status.
Big Number
150,300. That’s how many endangered species are on the International Union for Conservation of Nature and Natural Resources’s Red List. Of the 42,100 species threatened with extinction, mammals make up 27%.
What To Watch For
The team is looking into whether custom sound systems can be used to guide endangered species like the Southern white rhino out of known poaching areas in South Africa and into safety. So far, the use of human voice recordings to keep rhinos away from certain areas has been successful.
