Usually when I see them around the creeks, it's just far enough to still be cool; but not so close that they can't hear you. Just my experience, but bears seem to be the most likely critter to spook. Deer/elk can hear you coming and they stop and wait until actually seeing you before running. Cats will have a stare down and then vanish instantly right before you get the scope on them. But bears hear a twig break and just take off.