Human conversation scares African wildlife more than lions, new study finds

Quirks and Quarks7:37Human conversation scares African wildlife more than lions

They say words can't hurt you but to wildlife they can still be terrifying. A new study led by a Canadian researcher showsthat for a widerange of African wildlife the sound of human voices is scarier than the continent's top predator the mighty lion.

"We are super lethal," professor Liana Zanette toldQuirks & Quarkshost Bob McDonald.

"Humans kill medium sized carnivores, such as raccoons and skunks, at five times the rate at which large carnivore predators do, and we kill those large carnivores at nine times that rate. This is why we are called a super predator."

Zanette is a professor of biology and head of the Ecology of Fear lab at Western University in London, Ont.. She led an experiment in Africa that looked at the response of zebras, elephants, leopards, hyenas, giraffes and other species to the sound of humans, and compared it to how the animals responded to sounds of lions.

The research was published in Current Biology.

Zanette travelled to Greater Kruger National Park in South Africa. It's home to one of the largest populations of lions on the continent, and many prey species includingzebras, elephants, rhinoceros, antelopes and giraffes, as well as other predators such as hyenas and leopards. A total of 19 species were part of her study.

For her experiment, Zanette set up a video cameras in trees near a watering hole. When animals walked past, the motion would trigger the the video recording and sounds from a speaker.

"We did this in the dry season, and so water for animals is a pretty scarce resource during this time in South Africa," Zanette said.

"And so we trained our cameras on water holes because we know that animals are going to come to drink. And also, lions kill at water holes."

The sounds played on the speakers includedpeople talking, sounds of human hunting like gunshots and dogs barking, or lions growling and snarling.

Zanette was surprised to find that the sound of humans simply speaking inspired the most fear in the animals studied more than the sound of gunshots ,dogs, and lions. That fear was measured in two ways; whether or not the animals ran away,and also thespeed of their escape.

"They were two times more likely to run when they heard the sounds of humans talking compared to even lions," Zanette said.

"And they left the water hole 40 per centfaster as well.... 95 per centof the animals that we surveyed responded in this way."

Zanette believes that the fear of humans throughout the mammal community is further evidence of the environmental impact we have. Like the effect of climate change and habitat loss on animals, she thinks we need to start thinking about the ecology of fear for conservation purposes.

"It's remarkable that hearing humans speakinginspired the most fear in these animals."

Written and produced by Mark Crawley