Here's a quick video I shot last week while filming the north American Beaver (Castor canadensis). The more time I spend in the woods the more I've gravitated to beaver ponds. I've come to sincerely appreciate these ecosystem engineers and it's always easy to find a great set of tracks in the mud.
If you turn the volume up you will notice a chirp near the end of the clip (~14 seconds). Also note that at the end of the clip the beavers were trying to move the camera. I have 10 minutes worth of video in which multiple beavers try to work the camera free. Beavers certainly are determined and well adapted mammals, but ultimately it was the curiosity of a black bear cub that did this camera in.