I am paranoid about vicious dogs so I have a small spray can of pepper spray duct-taped to my hiking stick. I don't know if it would deter a rabid animal or a bad dog, and I hope I never find out!
Steve and I have a system for when I'm caching and he's not. There is a way to call our voicemail without making the phone ring. Just before I head into the woods I call with the time, the waypoint name and the co-ords. When I come out, I call to clear. Then I head to the next cache, call just before I head in, and so on. That way if I fall and knock myself out or whatever, he knows where to send the rescuers. The system only works if there is cellphone reception where I am caching.
~*There's Tupperware in thum thar hills!*~