Conservation scientists in South Africa are injecting rhino horns with radioactive isotopes. The doses are too weak to harm the animals, but strong enough to set off nuclear security system alarms at international border crossings.

In an effort to combat the poaching of rhinos in South Africa, the Rhisotope Project is injecting radioactive isotopes into rhino horns to deter traffickers. Injecting a small amount of radioactive material into the horns makes them detectable by radiation portal monitors already deployed at borders,

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.