Here’s an article from the New York Times about a special project within the National Parks Service to record natural sounds in the parks, and use them for study purposes. The article includes an audio file of a grizzly bear destroying the microphone.
It’s One of North America’s Quietest Places. Along Came a Bear…. – The New York Times
And here’s a link to the National Parks Service Natural Sounds & Night Skies Division website, with all kinds of resources about audio, recording sounds in nature, AND a library of sounds they’ve recorded.