I'll just add that going along with what calzoom was saying, generally speaking if you just make some noise while hiking, the four legged critters will do everything they can to get out of your way. I've stumbled across a few bears before, every time but one they took off away from me the second they sensed me. The only exception to this I've ever had was hiking with a group on a trail that hadn't been used in years. We had stopped to cook lunch and had a bear wander up to about 50 yards of the camp. It circled around, staying always about 50 yards out, sniffing around, seeing what we were (probably had never seen a human before in this area). After it got the smell of everything it just wandering off back into the woods.
While your hiking, talk to people around you, and intentionally step on sticks now and then to make noise. So long as most critters know your coming ahead of time, it's no problem. Just try not to suprise them. If something is camped in the middle of a trail, just pass around it giving it a wide margin of comfort, and stay with your group if your with one.
"Speak softly and carry a big stick"