A tour group on snowmobiles rides past the entrance to Yellowstone National Park February10, 2001. | Michael Smith/Getty Images

Animals Can No Longer Escape Human Noise Pollution in the US

Millions of hours of recordings made in national parks and other protected areas reveal what 'nature' in the US often sounds like: roaring airplane engines, accelerating cars, and clattering factories.

Published On 05/04/2017
2:06 PM EDT
Pine siskin singing as a car passes by, Rocky Mountain National Park. | Jacob Job
National Park Service staff set up an acoustic recording station in the temperate old-growth Hoh rainforest of Olympic National Park, Washington. | National Park Service