I once saw a turtle so big the people who caught it had chained it to a dumpster to prevent escape. The guy had caught one before of similar size; he gave it to the Memphis Zoo. The zookeepers estimated it to be just over 100 years old. Both were snapping turtles, but not the "alligator" kind (black with yellow stripes & such). The one i saw was about the size of a ATV, a bit wider. I don't think it cared much for hygeine (whew!).