A guy driving a truck in the middle of nowhere...

A guy driving a truck in the middle of nowhere picks up a hitch-hiker. It gets dark and the hitch-hiker falls asleep. Suddenly bang, and the hitch-hiker wakes up,"what the hell was that?". The truck driver replies, "some kinda animal, go back to sleep." Further the same thing again, bang, "What the hell was that?", "some kinda animal again." Further into the night, bang, bang, bang, "What the hell was that?", "Some bastard!". "How terrible",says the hitch-hiker, "but there were 3 bangs" The truck driver replies, "Yeah, well I had to go through two fences to get the bastard. . ."