By Mark Jenkins Photographs by Gulshan Khan The lion charges the electric fence, and I leap backward. “These lions are not accustomed to humans,” Casper van der Merwe says in his distinctive Afrikaner accent. I am standing less than five feet from five very large, healthy, well-fed lions, nothing but strands of wire separating us. The wire is supposed to be electrified, but I catch a lion licking it to no ill effect. Another young female charges me but is stopped by an older lioness, who bats her on the nose with a huge paw. “We only feed them twice a week, and we throw the meat over the fence,”…