The last few days have brought some interesting "critters" into my yard, right next to the house. The Oklahoma brown Tarantula and today, a very long (about 6') black snake. Just how dangerous are they, and should I attempt to kill them when they come in so close? I fear being bitten while working the flower beds. Are they aggressive? I just gave them plenty of room, as I don't kill things, unless they are hazardous to my health, as a rule.