Since Florida’s frontier days when cattlemen drove their herds through the state’s vast fields and forests, ranchers and native panthers have been natural enemies. The ranchers seek to nurture and protect their calves, while the panthers see them as prey. Human development won the battle, driving the large, tawny, cats to the brink of extinction before successful efforts to restore them began decades ago. But with Florida’s panther population recovering, some farmers complain the protected 6-to-7-foot long predators are once again killing their calves. …