Hearing people talk can terrify even top predators such as mountain lions, with consequences that ripple through entire ecosystems.
By Ed Yong

In the summer of 2017, the mountain lions, bobcats, and other residents of the Santa Cruz Mountains were treated to the dulcet tones of the ecologist Justin Suraci and his friends, reading poetry. Some of the animals became jittery. Others stopped eating. A few fled in fear.

Suraci, who’s based at the University of California at Santa Cruz, wasn’t there to see their reactions. He and his colleagues had strung up a set of speakers that would regularly play recordings of human speech in an area where people seldom venture. And they found that, the quality of the poetry aside, even the gentlest of human speech can make wild animals—even top predators—unnerved and watchful, in ways that shake entire food webs. It’s the clearest demonstration yet that we are among the scariest of animals—a super-predator that terrifies even the carnivores that themselves incite terror.

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His team has shown that they certainly do. In an English forest, the researchers played the sounds of various carnivores to local badgers. The badgers ignored the sounds of wolves entirely and were mildly concerned by the growls of wolves and bears. But they were profoundly disturbed by human speech, even the genteel tones of some BBC documentaries and a reading of The Wind in the Willows.

Next, the team wanted to see whether a larger carnivore would behave similarly. In the Santa Cruz Mountains, they placed speakers at sites where mountain lions had killed large prey and were regularly returning to feed. When the cats approached, the team played either talking humans or croaking frogs. The frogs didn’t faze them. The human voices—including those of Rachel Maddow and Rush Limbaugh—made them flee more than 80 percent of the time. “We thought it would be funny to play political commentators,” says Suraci. “But when we had to score the videos, and listen to Rush Limbaugh all the time, it wasn’t very enjoyable.”

...https://www.theatlantic.com/science/archive/2019/07/humans-predators-mountain-lions-landscape-of-fear/594187/?lctg=65a5cf6750d57dd73f085735