I figured with my 6' chain link fence around most of yard and a wooden fence with square fencing attached would help. My puppy is a little over 100lbs now; named Ruger and is a Great Pyrenessee. His sire weighs 180lbs. Had a bear a week or so ago climb the wood fence, break my third bird feeder then decided to come around back of house to side door. Ruger was barking up a storm at 5:30am. I don't keep food stuff in garbage but forgot had some rancid grease. Bear started on garbage bag but barking stopped him, I think. Took my 45/70 to see if he was inside fenced area before letting Ruger out. I never would have thought animals still come near an area where a dog that big lives. No effect on copperheads, ground hogs, etc.