New technology detects the shockwave of a supersonic bullet traveling through space, which cannot be muffled, to track poachers shooting at elephants and rhinos.
Nepal's successful anti-poaching measures are a model for other countries, while African rhino-range countries excel at marketing wildlife tourism.
In 2005, conservationists launched a plan to establish rhino populations in seven parks in Assam state. It proved to be an even bigger challenge than expected.
As poaching pushes the rhino toward extinction, South Africa considers a radical solution: Legalize the very thing that is killing them. It'd make some people very rich. But would it doom the species?
South Africa debates legalization of the rhino-horn trade to stem smuggling.