Us humans already claim so much more than our fair share of space on this planet. I think it's only right that we try and take precautions to avoid hitting the wildlife. I've only been in one situation where I could not stop in time to keep from killing an animal and that was because the bird dived at the window of my automobile while I was travelling 70MPH. Two nights ago, the sun was setting and I was racing it back to the trailhead. I was coming downhill on some fast doubletrack/fireroad and doing around 25MPH when a deer jumped out right in front of me and I was sure I would hit it but I managed to adjust my line behind it and missed it by about a foot. As I looked back, it stood there at the other side of the trail and just stared at me. As far as being attacked... birds seem to like my helmet or something. I've had them dive at me before.