 It is also possible that poachers could avoid this by cutting off the radioactive material. However, the value of horns that have been trimmed is much lower on illegal poaching markets, which is why the scientists say they are confident that this deterrence will work. They have now put the radioactive material inside an initial 20 rhinos as part of a trial run, and Professor Larkin says it will not harm them. I've spent the last two years doing dose calculations, creating a digital model of the rhinos' hair,