See how animals react to the scariest sound on the savanna | ET REALITY

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Panting after chasing the impala now in its jaws, a leopard drags its prey to a shady spot next to a waterhole. Before he can sit down to feast, a voice, seemingly out of nowhere, begins to speak calmly. “It is very difficult to speak Afrikaans…” the disembodied voice begins. The leopard pauses, looks toward the source of the sound, and then drops its hard-won prey and runs.

This leopard has unknowingly abandoned its lunch in the service of science. Researchers analyzed thousands of video recordings to reveal a hierarchy of fear in a set of mammals living in and around Kruger National Park in South Africa. While lions have been dubbed the king of the beasts, the videos show that for wild savanna mammals – from small antelopes to gigantic elephants – the most terrifying and deadly predator of all is us.

Researchers found that the sound of human voices evokes more fear than the sounds of lions snarling and snarling. This underscores that our species is recognized as uniquely dangerous, “because we are super lethal,” said Michael Clinchy, a conservation biologist at Western University in London, Ont.

Researchers hope that understanding this universal fear of humans can contribute to the goal of preventing wildlife poaching.

The studio from which the videos come, published Thursday in the journal Current Biology, is the latest in a series by Liana Zanette, also of Western University, and Dr. Clinchy, whose team studies fear. Dr. Zanette, Dr. Clinchy, and their colleagues have shown that it is not just being eaten, but the fear of being eaten that creates profound effects that extend from individuals to entire communities. So, returning to the savannahs of South Africa, where a diversity of mammals have evolved over millennia alongside lions and human hunters, Dr. Zanette and Dr. Clinchy became curious: where did humans rank on the scale of terror among these mammals?

Working with local South African colleagues and other collaborators, the researchers set up equipment that has tested the fear responses of several animals. Automated motion-activated behavioral response systems record videos of passing mammals as they respond to a mix of sounds on a spectrum from potentially frightening to harmless.

The researchers placed recorders and speakers in trees near 21 water holes, habitats that thirsty animals were reluctant to leave during the dry season, when the research was conducted. The devices ran 24 hours a day for six weeks, playing clips of sound types in random order when activated by motion.

The benign sounds (the control in the experiment) were the songs of local birds. The most threatening sounds were dogs barking, gunshots, lions growling, and humans talking calmly.

The human voices included women and men speaking in Tsonga, Northern Sotho, Afrikaans and English, drawn from selected South African news clips, with some football of course, in case the mammals were missing sport.

The researchers paid close attention to equalizing the volumes of all sound types, so that any potential fear was a result of the content, rather than the volume. To achieve this, they used the sounds of lions’ growls and growls instead of their much louder roars.

The team chose running away as a common, easy-to-measure measure of behavior. Each video was scored based on the speed at which an individual animal ran and the time it took to leave the water hole.

Analysis of more than 4,000 videos, focusing on 19 species, revealed that when faced with humans talking, the animals were twice as likely to run and leave waterholes 40 percent faster than when they heard lions, dogs or Firearms.

The contrast in flight response to human voices and lions’ growls and growls was pronounced in most species, including giraffes, leopards, hyenas, zebras, kudus, wild boars and impalas.

Like other savannah mammals, elephants fled when they heard human voices.

“They just ran out of there,” Dr. Clinchy said.

But when it came to their response to lion sounds, elephants were a notable exception. Instead of fleeing, the elephants ran toward the source of the sounds, and in some cases crashed violently into the devices.

“The elephants gave us a lot of headaches,” Dr. Clinchy said. In one video, recorded at night during lion breeding, an elephant breaks the recorder, the camera goes black, and the elephants trumpet as they leave.

Elephants’ aggressive reactions toward lions are well known, said Karen McComb, an animal communication researcher at the University of Sussex whose team conducted acoustic studies. experiments about elephants in Kenya. Upon hearing the sounds of lions, he explained, elephants often groupdefending the babies and moving towards audio recordings of lions.

“They never did this with our reproductions of human voices,” Dr. McComb said. “Elephants are big enough to be able to harass and scare away lions,” he added, but against humans armed with spears or guns, getting close could be fatal.

In the new study, researchers were intrigued by the rhinos’ responses. Rhinos fled from human voices twice as fast as lion sounds. And during the research period, five endangered southern white rhinos were poached in nearby reserves. So one of the applications the team wants to explore in future research, Dr. Clinchy said, is whether using human voice playbacks could keep animals away from fences near roads, where a lot of poaching occurs.

Chris Darimont, an ecologist at the University of Victoria in British Columbia who was not involved in the study but reviewed the paper for the journal, praised it although he noted that focusing on sounds was a limitation. He hoped future research would incorporate olfactory cues.

“We might expect to find even more surprising human impacts, given the nature of olfaction, the enormous sensitivity of mammalian olfaction, and the ways in which odors can persist,” Dr. Darimont said.

Ishana Shukla of the University of California, Davis, who studies mammal responses to human disturbances, praised the breadth of the study. By looking at the reaction to human disturbances across the entire mammal community, she said, “we can get a bigger picture of what’s really happening to the system, rather than just a moving part.”

As for the Kruger lions, they seemed unfazed by human intruders who used their growls for scientific purposes.

Once, leaving by truck after two hours assembling and testing an elephant-proof recorder, Dr. Clinchy and Dr. Zanette realized that the lions had been secretly making their own field observations of them.

“This lioness that was on the other side of the water hole got up out of the grass and walked away,” Dr. Zanette said. “She was there the whole time!”

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