The procedure, according to the researchers, has proven to show no harm to the rhinos themselves, while making the horn “useless” and “poisonous” to humans. (Photo via IAEA)A South African university launched an anti-poaching campaign on Thursday (July 31) with a unique approach – injecting radioactive isotopes into rhino horns. It claimed that the method is harmless for the rhinos and allows customs agents to detect trafficked horns.
After six years of intense research and testing, the University of the Witwatersrand, supported by the International Atomic Energy Agency (IAEA), formally launched the Rhisotope Project. Five rhinos were administered radioactive isotope injections in the Waterberg Biosphere Reserve.
The university hopes the initiative will mark the start of mass treatment of South Africa’s declining rhino population.
How the isotope tagging works
According to the IAEA, radioactive isotopes or radioisotopes are the unstable form of an element that emit radiation to transform into a more stable form. The radiation can be traced, and typically causes changes in the substance it falls upon.
Through a non-invasive procedure, rhino horns are tagged with low doses of radioactive isotopes, allowing for their ready detection by radiation portal monitors (RPMs) already deployed at borders, ports, and airports worldwide to identify unauthorised nuclear materials.
The injections being administered to rhinos. (IAEA photo)
To test this system, the researchers used 3D-printed rhino horns with identical shielding properties to real keratin, which is the substance that makes up rhino horn. According to the university, the tests confirmed that individual horns could be detected inside full 40-foot shipping containers.
The procedure, according to the researchers, has proven to show no harm to the rhinos themselves, while making the horn “useless” and “poisonous” to humans.
“We have demonstrated, beyond scientific doubt, that the process is completely safe for the animal and effective in making the horn detectable through international customs nuclear security systems,” James Larkin, the project’s Chief Scientific Officer, told the Associated Press.
The university also announced the results of the pilot phase undertaken last June, when it injected radioisotopes into 20 rhinos at the Waterberg Biosphere in Waterberg, Limpopo, about 250 kilometres north of Johannesburg in South Africa. A team from Ghent University, Belgium, monitored the health and conducted cytological examinations on 15 treated rhinos, comparing these results with five untreated animals.
The team used the biological dosimetry technique to culture blood samples and examined the formation of micronuclei in white blood cells, which indicates cellular damage. They found no such damage to the 20 rhinos in the pilot phase.
“This has been an international collaboration of like-minded individuals who are trying to make a real difference to this poaching crisis,” Larkin added. “We started with the question – what if radiation could protect rather than harm, by turning rhino horns into traceable markers that stop poachers before they trade? After two years of digital modelling, safety testing and detection simulations, we’re ready to roll out a solution that could truly reduce rhino poaching.”
According to the International Union for Conservation of Nature, the global rhino population was estimated to be about 500,000 at the start of the 20th century. It has since dwindled to 27,000, owing to the burgeoning demand for rhino horns. These horns are trafficked to Asian markets where they are used in traditional medicine, and also as as a status symbol.
South Africa, home to the world’s largest rhino population, had lost over 10,000 rhinos to poaching over the last decade, with 103 losses reported by the South African Ministry of Forestry, Fisheries and the Environment in the first quarter of this year.
While the project itself is not a cure-all or silver bullet to curb poaching, the researchers hope it will prove to be a great deterrent. It would certainly prove to be less disruptive to rhino behaviour compared to dehorning, in which rhinos’ horns are removed to deter poaching. While a 2024 study published in the Science journal showed that dehorning rhinos reduced poaching by 78 per cent over seven years on eight reserves, another study the previous year established that this measure impacted their ability to socialise with their peers and noted reductions in the sizes of their home ranges.
The researchers are now looking to recreate the success of this project in protecting other endangered species, such as elephants or pangolins.
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