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,

Scientists in South Africa are injecting rhinos with radioactive material to enable them to track illegal trade and deter poachers.