What? Just kidding!
The only readily available measure of hearing acuity for various animals is frequency range. I've found conflicting information on how deer compare to humans in this regard. For humans it's under 0.1 to over 10 kHz. For deer, I've seen 2-6 kHz but I've also seen that deer can hear higher frequencies than we can. I don't have information specific to other American mammals, but it's probably out there.
Deer are generally recognized as having very acute hearing. Hearing is their primary means of detecting potential danger. They are able to move their ears independently and so can pinpoint sound sources' direction and distance very accurately.
For more thorough (and perhaps more consistent) coverage of this topic, you might want to pick up a copy of the following article: Miller, K.V. 2003. Life of the White-tailed deer: How well do deer hear? Georgia Outdoor News 1:120-121.