I was camping in Tarangire National Park one night and heard gunfire. We asked our guides if those were poachers, and he said they were not. The park could not sustain the number of elephants it held, so the elephants had to leave the park at night to raid the fields of the surrounding farmers. The shots we heard were the farmers trying to scare off the elephants to save their crops. It really blew my mind to realize that even those big national parks that I'd grown up reading about and seeing documentaries about weren't large enough to support viable, sustainable populations of some of the larger mammals.