My experience with Timber Rattlers is they are about the most docile snake you could hope for. They won't necessarily rattle to warn you, but they are not quick to bite. Copperheads where I live are abundant and have a little attitude, just watch where you sit or put your hands. Probably not the end of the world if one bites you, just sit down until the swelling goes down. If it turns out you are allergic to the venom, that's bad Cottonmouths scare the heck out of me because they often stand their ground (or advance on you). I watch where I step around water and give them a wide berth. They just look mean.