A South African university has launched an anti-poaching campaign to inject rhino horns with harmless radioactive isotopes that customs agents can detect.
In a collaborative project involving the University of the Witwatersrand, nuclear energy officials and conservationists, five animals at a rhino orphanage have been injected in what the university hopes will be the start of a mass treatment of the declining rhino population, The Associated Press reports.
The program began at a preserve in 2024, when scientists injected about 20 rhinos with isotopes in medical trials. Even at low levels, radiation detectors can recognize the isotopes at airports and borders. The researchers said that tests have confirmed that the radioactive material does not harm the animals.
“Even a single horn with significantly lower levels of radioactivity than what will be used in practice successfully triggered alarms in radiation detectors,” said James Larkin, chief scientific officer on what is called the Rhizotope Project.
The tests also found that horns could be detected inside full 40-foot shipping containers, according to AP.
The rhinos are at the orphanage in Mokopane, South Africa, because poachers shot their mothers.
“Now with the Rhizotope Project, you can’t take that horn anywhere,” PBS reporter John Yang said. “It is radioactive. You can’t take it through any airport, any harbor, any customs office. Sirens go off. It is wonderful. I’m telling you, this could be the holy grail to save this species.”
The International Atomic Energy Agency supports the effort. Scientists are working to see whether the idea can be applied to other species prized by poachers. The scientists also urge wildlife park owners and national conservation authorities to have their rhinos injected.
The technology is already in place for detecting radioactive horns. All over the world, security teams screen for radioactive material on the move, according to Wired magazine. “This monitoring takes many forms, including covert detectors hidden in the walls at airports that silently scan passengers,” the magazine reported. Customs officials often are equipped with handheld radiation-detection devices, while drones, loaded with sensors, “can fly across wide areas while searching for lost radioactive objects.”
Rhino horn has been prized for centuries in the Middle East and Asia for use in carvings. But in modern times, it is used in Asian medicines, particularly traditional Chinese medicine.
In Chinese medicine, the horn is shaved or ground into a powder and used to treat fever, rheumatism, gout and other disorders. A 16th-century Chinese pharmacist said it could be used to treat headaches, poisoning and typhoid, and his teachings persist to this day. But the horns are composed of keratin, as are human fingernails, and have no medicinal value.
Rhinos are big business for poachers. At the beginning of the 20th century, the world rhino population was believed to be about 500,000, according to the International Union for Conservation of Nature. The current rhino population is only about 27,000, because of the continued demand for rhino horns on the black market.
South Africa has the largest population of rhinos with an estimated 16,000, but the country sees high levels of poaching with about 500 rhinos killed for their horns every year, AP reports.
One strategy to protect rhinos from poaching has been to carefully remove their horns. Environmentalists in Namibia pioneered the process in 1989, according to the environmental group Save the Rhino. Over the next decade, dehorning, along with improvements in security and funding for rhino protection, seemed to be working, with no dehorned rhinos poached in Namibia. At that same time, South Africa and Zimbabwe reported a reduced rate of rhino poaching because of the process.
But dehorning has not been entirely successful. In Zimbabwe’s Save Valley Conservancy, six newly dehorned rhinos were poached in eight months in 2022, with two killed within days of being dehorned. The demand for rhino horn meant that, despite removing 90% of the horn, poachers were killing rhinos for the remaining 10%, according to Save the Rhino.
It was also reported that some poaching gangs were killing rhinos out of vengeance, to avoid tracking the dehorned animals a second time, and to show authorities that they would not be stopped.
The nonprofit organization Helping Rhinos says there are established practices for protecting rhinos long term and enabling them to safely reproduce. They include:
- expanding wildlife habitat
- dropping fences to encourage natural migratory behavior
- restoring and “rewilding” degraded wildlife habitat
- relocating rhinos to establish new rhino populations
- bringing together regional experts on range expansion best practices
Helping Rhinos also recommended creating “rhino strongholds.” These are areas that provide the best possible security to reduce the risk of poaching and are large enough to let rhinos demonstrate natural behaviors, “including migration between territories and genetically diverse breeding, without the need for hands on intervention by humans.”
