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People’s voices frighten wildlife in the savannah even more than the growls and snarls of lions, suggesting that we are the scarier predator.

Giraffes, elephants, impalas, rhinoceroses, leopards and more than a dozen other species of mammals in a South African wildlife reserve ran away from loudspeakers twice as often when they heard the sounds of humans compared with those of lions, found a study led by at the University of Western Ontario in Canada.

“Theoretically, this is a protected area, so these animals should not be fearful of us,” he says. “But [our study implies that] if you’re a wildlife tourist, or a poacher, or whatever, you’re all going to be perceived as the same thing. The presence of the human is equally malignant, regardless of what type of human you are.”

Clinchy and his colleagues had already discovered that . Wanting to find out which was the most feared, the team decided to test humans against lions — often perceived as the world’s most fearsome predator on land, says Clinchy.

They set up loudspeakers and cameras on trees 10 metres away from animal paths near 21 waterholes in Greater Kruger National Park, South Africa, which hosts one of the largest remaining lion populations in the world.

When animals approached the waterholes, the speakers automatically played back one of four kinds of audio recordings, all at the same volume. These included men and women speaking calmly in local languages and dialects, lions snarling and growling, gun shots with or without barking dogs and the calls of regional birds like hoopoes and wood owls.

Although the animals live inside a sanctuary, they can regularly hear visiting tourists speaking to each other, as well as guns and dogs during rare organised hunting events or illegal poaching.

The researchers captured 15,000 videos of 19 species of carnivores and herbivores reacting to their recordings. They found that wildlife ran around in response to human voices more than to any other sounds, and were also 40 per cent quicker to flee – abandoning the water hole even during the dry season – when hearing humans compared with lion or hunting sounds. The animals were unlikely to have learned these fear reactions through their limited exposure to humans, says Clinchy. “It does seem to be ingrained.”

The only species that didn’t flee people’s voices were the lions themselves. “The lions didn’t run from anything,” he says.

The findings build on previous studies of animals’ strongly fearful reactions to humans in North America, Europe, Asia and Australia, highlighting the damaging impact that our presence can have throughout wildlife habitats. “Just the fear of us could potentially be having significant ecological consequences,” says Clinchy.

Even so, the findings could lead to positive outcomes as well, he adds. Human vocal recordings might deter wildlife from entering crop fields or livestock farms, or even protect rhinoceroses from roaming in zones where horn poaching is more likely to occur.