The purpose of the bell is to let the animal know you're coming. The best advice in dealing with wild animals is to never confront them in the first place. Keep your distance. If you want to get closer, go to a zoo.,
Any animal will attack if you get too close, whether that's intentional or by accident. Even a timid opossum will defend itself if you corner it. The good news with these carnivores is that humans are not on their food list, but they will come after you if they see you as prey. So don't look like prey.