It's no secret that the news cycle in the United States has become mighty heated and polarised. And it turns out human beings aren't the only ones turned off by the jabber. 

Well, in truth, the latest study out of the Santa Cruz Puma Project doesn't really have much to do with political discourse – but it nonetheless produced the unique spectacle of big cats scramming at the sound of Rush Limbaugh, Rachel Maddow, Amy Goodman and Glenn Beck.

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The sound of human voices turns mountain lions into scaredy-cats. And that fear has ripple effects all the way down the ecosystem. Image: Sebastian Kennerknecht/

Potential feline opinions on American punditry aside, the research – written up in a new journal article in the Proceedings of the Royal Society B – does reveal some sobering insights into puma ecology and the ripple effects humankind casts down an ecosystem.

Led by former University of California-Santa Cruz grad student Justine Smith, the researchers set out to investigate the cats' response to the sound of human voices. The team located fresh puma kills via GPS data obtained from collared cats, then installed motion-sensor audio equipment and cameras near the carcasses. 

When pumas – also known as cougars or mountain lions – crept in to feast, they triggered playback of either human voices or, as a control, the croaks of native Pacific treefrogs. Only once did the recorded frog song spook a cat off a kill. In contrast, commentator chatter sent the mountain lions immediately hightailing it 83 percent of the time.

The team culled audio from high-profile media personalities like Limbaugh and Maddow only because of the recordings' high fidelity. It didn't matter, incidentally, whose voice was being played. Smith's tongue-in-cheek conclusion, as shared with The Washington Post? "Pumas are nonpartisan in their hatred of American politics."

Not only did the cats flee from the sound of people talking, but the disturbance also warped their overall dining experience. "We found that pumas took longer to return to their kills after hearing people, and subsequently reduced their feeding on kills by about half," Smith said in a UC-Santa Cruz news release. "Those behavioural changes are significant, as our previous work has shown that they cause pumas to increase their kill rates by 36 percent in areas with high human activity."

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Puma researcher Justine Smith uses telemetry gear to track pumas in the Santa Cruz Mountains. Image: Sebastian Kennerknecht/

This touches on an ecological concept called the "landscape of fear". The impact of predators on prey species isn't restricted to direct killing: their spectre alone also keeps prey animals on guard – prompting them, for example, to keep moving, feed more fleetingly, and to favour or avoid certain habitats depending on how vulnerable they are within them.

Pumas summit the food chain in the coastal ranges of California, but this research suggests they may see us as something of a "super predator", as the study's authors put it. We don't simply shoot mountain lions, crush them on the blacktop, and pulverise their habitat with subdivisions and highways – our mere presence, the "landscape of fear" we establish, seems to stress them out.

And by bumping pumas off their kills, human activity can spell bad news for the black-tailed deer at the heart of the local mountain-lion menu. The big cats may be forced to hunt more often to compensate for those abandoned (or at least abbreviated) meals.

"Fear is the mechanism behind an ecological cascade that goes from humans to pumas to increased puma predation on deer," noted UC-Santa Cruz Associate Professor of Environmental Studies Chris Wilmers, another member of the Santa Cruz Puma Project and one of the new study's senior authors. 

"We're seeing that human disturbance – beyond hunting – may alter the ecological role of large carnivores," he said. "As we encroach on lion habitat, our presence will likely affect the link between top predators and their prey."

The new research supports the Santa Cruz Puma Project's broader investigations of puma behaviour in the Santa Cruz Mountains and the ecological impacts of habitat fragmentation.

Meanwhile, we've reached out to Rush Limbaugh and Rachel Maddow for comment and will update accordingly. (Kidding!)