A South African university has launched an anti-poaching campaign to inject the horns of rhinos with radioactive isotopes, which it says are harmless to the animals but can be tracked by authorities.

South African scientists have launched an anti-poaching campaign in which rhinos' horns will be injected with a radioactive material. The group, from the University of the Witwatersrand, said the process is harmless to rhinos but will allow customs officers to detect smuggled horns as they're transported across the world.