For the pilot study, 20 rhinos were injected with the radioactive material last year, which proved that it was not harmful to the animals.

South African scientists have launched an anti-poaching campaign in which rhino's 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.