AP Photo

When poachers approach the Rhino and Lion Nature Reserve near Johannesburg, South Africa, they quickly learn that they won’t find anything of value there. Yes, the reserve is home to rhinoceroses, whose horns fetch top dollar—up to twice the price of gold—for use in traditional Asian medicine, but signs surrounding the park tell poachers that anyone taking “medicine” made from the horns is likely to get sick, not healthy. (Rhino horns, made of keratin, have no actual medicinal value.)