Researchers in SA are working on a potentially new method to deter rhino poachers and smugglers by using radioactive markers to make smuggled horns detectable at global ports of entry and less desirable to buyers.

SA is home to the world’s largest rhino population but has battled poaching for decades. The rhino horn is one of the most expensive commodities in the world by weight, fetching tens of thousands of dollars per kilogram.

Demand is mainly from Asia where rhino horns are believed to have potent medicinal properties and are also a symbol of wealth...