With its ears on alert high up in the Black Hills near Terry Peak, a whitetail deer stands as still as the cold, freshly fallen snow and golden aspen leaves beneath its feet. Research has shown that deer can hear upwards of 54,000 hertz, whereas humans can only hear up to 20,000 hertz if we’re lucky, thus humans make noises, we may not even know we’re making, but deer can hear them clear as a bell.