Why conservationists are making rhinos radioactive

Every year, poachers shoot hundreds of rhinos, fishing crews haul millions of sharks out of protected seas, and smugglers carry countless animals and plants across borders. This illegal activity is incredibly hard to disrupt, since it’s backed by sophisticated criminal networks and the perpetrators know that their chances of being caught are slim. With an annual value of $20 billion, according to Interpol, it’s the world’s fourth-most-lucrative criminal enterprise after trafficking in drugs, weapons, and people.

The United Nations seeks to end trafficking in protected species by 2030. But the environmental guardians facing up to these nefarious networks—dispersed alliances of rangers, community groups, and law enforcement officers—have long been ill equipped and underfunded. A recent report by the UN Office on Drugs and Crime found “no reason for confidence” that the 2030 target would be reached. 

Still, there is genuine hope that tech could help turn the tide. Tools initially developed for cities and research facilities are increasingly moving into the planet’s wild places, allowing environmental agencies and self-motivated communities in both richer and poorer countries to step up their efforts to detect illegal goods, trace smuggling networks, and prevent poaching at the source. 

In December, Interpol announced it had seized record numbers of live animals, thanks in part to a set of sophisticated tools that had helped to expose hidden networks behind trafficking. Its Operation Thunder 2025 coordinated law enforcement agencies from 134 countries and seized 30,000 live animals, from apes to butterflies, using a suite of technologies including digital forensics and AI-driven detection. “The success of Thunder 2025 shows that modern threats demand modern tools,” says José Adrián Sanchez Romero, an operations coordinator at Interpol’s environmental security subdirectorate.

Here are five examples of technologies that are arming conservationists and others in the battle to end wildlife crime. 

Tagging rhinos

In July, a group of South African researchers announced they had won government approval for one of the most eyebrow-raising attempts to prevent wildlife crime: drilling radioactive substances into the horns of rhinoceroses. 

In an effort dubbed the Rhisotope Project, the group worked in 2024 and 2025 to fit 33 rhinos from Limpopo Rhino Orphanage in South Africa with pellets containing low-level radioactive isotopes. The project is supported by the International Atomic Energy Agency. 

Blood samples and veterinary exams have shown that the pellets don’t affect the health of the rhinos, the rangers, or the surrounding environment. But the isotope emits enough radiation for the horns to be detected by radiation portal monitors, devices that can scan cargo containers and vehicles to detect illicit sources of radiation. Eleven thousand such monitors are already in operation at airports and shipping terminals worldwide, in addition to thousands of personal monitors worn by border security. In November 2024, Rhisotope tested the system at New York airports and harbors in collaboration with the US Customs and Border Patrol. The group found that border guards could detect an individual horn the team had planted inside a full 40-foot shipping container.

The project was pioneered by James Larkin, director of the radiation and health physics unit at the University of the Witwatersrand in South Africa. Though the country is currently home to 15,000 rhinos, the majority of Africa’s total population, poachers have killed 10,000 rhinos there since 2007. In the past, the common approach to deterring poachers was to eliminate the part they’re seeking, preemptively cutting off the animal’s entire horn. But dehorning requires rhinos to be sedated for long periods, and it’s a stressful and costly process that must be repeated every 18 to 24 months, as rhino horns grow back. The act also renders rhinos less able to protect themselves, and they tend to withdraw from social interactions and competition for mates.

The new approach is far less painful and time-consuming. Each dose costs 21,500 South African rand (about $1,300) per animal and remains active for five years. Warning signs along perimeter fences make it clear the animals have been tagged, helping to deter poachers. 

Larkin, who spent his career as a nuclear safety expert, says he was initially wary when conservationists suggested to him that radioactive substances could help prevent rhino poaching, joking that he didn’t want to end up in jail if anyone got hurt. But he changed his mind when he realized there was a dose that would be harmless to bystanders while making the horns both worthless to smugglers and readily detectable.

Poachers will kill a rhino for even a small amount of horn, which can fetch $60,000 per kilogram as an ingredient for traditional medicines. Adding isotopes, though, renders the horns potentially unsafe to consume, and it’s hard for smugglers to reverse: “It’s almost impossible to remove isotopes unless you are a skilled radiation protection officer who knows what they are looking for,” Larkin says. Even so, he’s tight-lipped about the compound the pellets are made from and what they look like: “I don’t want to help criminals,” he explains.

The South African health agency has now approved Rhisotope to roll out the program across the country. “We have a goal ultimately to treat up to 500 rhinos a year,” says Jessica Babich, chief executive of the project. At the same time, the group is working to adapt its approach to other popular poaching targets—elephant tusks and pangolin scales—as well as trafficked plants like cycads. 

Scanning signatures

For many exotic pets, from birds to pythons, there are two parallel trades: a legal one in farmed or captive-bred animals and an illicit one in creatures taken from the wild. But faced with a lizard or a parrot, how can law enforcement know its origin story?

In Australia, some conservationists have been trying to follow the numbers. It’s very hard to breed the egg-­laying mammals known as short-beaked echidnas. US zoos have yielded only 19 echidna babies, or “puggles,” in a century of efforts. So Indonesia’s yearly export of dozens of “captive-bred” echidnas has long raised suspicions. 

To address the issue, a team at Australia’s Taronga Conservation Society, led by Kate Brandis, has developed an x-ray fluorescence (XRF) gun that can analyze elemental signatures in keratin—the stuff of quills, feathers, and hair. Wild echidnas, for instance, forage for a diverse diet of beetle larvae, ants, and grubs, while captive animals tend to be raised on a low-diversity diet of commercial feed. Each of these dietary histories leaves a record in the mammals’ porcupine-like spines, which can be read with high accuracy using a handheld XRF gun. Similar evidence can be found in other species, like cockatoos, pangolins, and turtles, which the team has used to test the device. 

There is certainly plenty more to be done: Australia, home to many unique species that live nowhere else on the planet, is a target for collectors from Asia, Europe, and the US. Brandis is targeting some of the species most often trafficked out of the country, including shingleback and blue-tongue lizards. Not long ago, Australian environmental authorities led a trial study at post offices across the country, using the XRF gun alongside AI-equipped parcel scanners, which Brandis’s team had trained to recognize concealed species in real time. The trial uncovered more than 100 legally protected lizards that were being shipped out of Australia; a distributor was sentenced to more than three years in jail.

AI in the sky

Commercial fishing, scuba diving, and oil exploration are all prohibited in the Papahānaumokuākea Marine National Monument near Hawaii, an expanse of the Pacific larger than all US national parks combined. It is just one of a number of vast marine protected areas that have emerged in recent years, along with global pacts to conserve 30% of Earth’s land and sea. 

But establishing these reserves is just one step. Enforcing their protection is another matter. And for many marine reserves—especially those in the Global South—there is no real way to do that, says Ted Schmitt, senior director of conservation at the nonprofit Allen Institute for AI (AI2). Thousands of square kilometers of open ocean is a lot to monitor. Even with satellites scanning the marine areas, the reality until recently was that you had to know what you were looking for: “When you have the vastness of the ocean, you can have analysts who are very well trained, looking for vessels,” he says. Even then, there is little chance of finding wrongdoing without intelligence from the ground. 

In 2017, Microsoft cofounder Paul Allen began developing a tool called Skylight to provide analysts with more of that intelligence, using AI to help analyze satellite and ship-tracking data to detect suspicious behavior. The project moved to AI2 after Allen’s death in 2018, and the technology has since been adopted by more than 200 organizations in more than 70 countries. “We’re basically monitoring the entire ocean 24-7-365, and surfacing all these vessels,” says Schmitt. 

To see how coast guards use the system, Schmitt points to a series of arrests in Panama in early 2025. That January, satellites found 16 boats about 200 kilometers off the coast inside the Coiba Ridge marine reserve, which serves as a migratory highway for sharks, rays, and large fish like yellowfin tuna. Skylight’s AI algorithms, trained to recognize the signature movements of various types of fishing, detected long-line fishing and requested higher-resolution images of the site from a commercial satellite flying overhead. The images and Skylight’s analysis were used by Panama’s environmental agency and military, which deployed ships and aircraft to the area, ultimately seizing six vessels and thousands of kilograms of illegally taken fish. 

Skylight AI detects around 300,000 vessels per week, according to the company’s platform analytics. Stories like Coiba Ridge make clear that AI can benefit partners who are working tirelessly on the ground, says Schmitt: “The Panama case really was one of those ‘wow’ moments, not because the technology finally proved itself, but because the agencies that needed to operationalize it, and actually take it to a legal finish, did it.”

Rapid DNA tests

When the conservation scientist Natalie Schmitt was researching snow leopards in remote areas of Nepal, she worked with people who could point out signs of these elusive big cats—often a pile of droppings. But the results weren’t reliable: Leopard scat can easily be confused with the poop of wolves and foxes, which share the same habitat and prey, she explains. What Schmitt wanted was a tool that could identify the animal involved, right on the spot—ideally by finding a way to sequence the DNA in the scat. 

While some laboratories can take DNA samples of such material and identify species of interest, they are few and far between in rich countries and usually nonexistent in poorer countries, meaning that this process can be weeks long and involve shipping samples cross-country or across borders. This is a problem not just for field research but for wildlife trafficking enforcement. Imagine a border agent who has just opened a box of shark-like fins or a shipment of live parrots and needs to know whether the particular species is one that can legally be captured and transported. People in this situation don’t have weeks to spare.

In 2020, Schmitt founded WildTechDNA, which has developed a DNA test that aims to do that work on the fly. The test, which is about as easy and fast as a home pregnancy test, employs a simple two-step process. First, a new extraction method—“Literally, put the sample in the extraction tube and squeeze 10 times,” she says—can cut the time it takes to pull DNA out of a sample from a day to about three minutes. Then, to actually test that DNA, the company took inspiration from the covid pandemic. The researchers found they could use technology similar to rapid at-home tests to identify whether the DNA in question belongs to a specific species: “Our tests use very simple lateral-flow strips to tell you whether a sample belongs to your target species of interest, yes or no.”

The strips can be tailored to test for a wide range of targets, from big cats to microbes, opening up diverse applications in the wild. They can tell if samples of hair belong to a snow leopard, or if a frog has been infected with the fungi that cause chytridiomycosis, a disease that has devastated amphibians worldwide and wiped out at least 90 species. 

WildTechDNA’s earliest adopter was the Canadian government, which wanted to detect European eels—a critically endangered species that is effectively impossible to identify by appearance. This confusion has allowed €3 billion of European eels to be smuggled each year, disguised as other eel species. Some of that passes into Canada on its way to suppliers in Japan and China, and in some cases on to Canadian restaurants and consumers. “When a shipment is suspected to contain European eel, they’ll randomly sample it and they’ll send those samples off to a lab across the country, which will take three weeks,” says Schmitt of traditional tracking methods. WildTechDNA developed tests specific to European eels and taught Canadian enforcement officers how to use them, so that they could launch a “nationwide European eel blitz,” she says.

In a 2025 campaign, European eels turned up in fewer than 1% of shipments. Schmitt says Canadian authorities have not disclosed details about investigations but are encouraged by the results—significantly below the rates detected using older technologies in 2016, an improvement they attribute to better surveillance.

Listening in

The world’s forests are increasingly filled with snooping devices. In addition to affordable camera traps and animal-mounted GPS tags, low-cost solar-powered microphones have proved to be strikingly effective at revealing what’s living in some of the planet’s most densely inhabited and biodiverse environments. 

Rainforest Connection, a nonprofit founded by the physicist turned conservation-­tech entrepreneur Topher White in 2014, was a pioneer in bioacoustic monitoring for conservation. The group initially repurposed old phones into low-cost monitoring devices but has since developed a standardized device called the Guardian that has now been deployed in more than 600 locations. 

Guardians are designed to capture a broad soundscape of the rainforest: “They sit out in the rainforest for long periods of time, up in treetops. They’re solar-powered, they can last for years, and we listen to all the sounds continuously and transmit that up to the cloud, where we are then able to analyze it for all sorts of things,” says White. From the outset, the aim was to use these devices to pick up immediate threats—“chainsaws, logging trucks, gunshots, things like that,” White says—and relay real-time alerts to local partners, including police, Indigenous groups, and local communities that protect the land.

Bioacoustic monitoring devices have rapidly advanced in recent years. Many can now analyze data before transmitting it, and they’ve become cheaper to make as batteries have gotten smaller. By today’s standards, Rainforest Connection’s sensors are “over-engineered,” says White. But having a large number of detectors already deployed means there is ample data that can be mined for signals beyond well-known red flags, like gunshots. “An area for a lot more innovation going forward is to use the soundscape itself as a detector,” White says. Rainforest Connection and the German software firm SAP tested this approach on the island of Sumatra and found they could identify human intruders by using machine learning to hunt for “uncharacteristic sudden changes to the soundscape.” For example, tracking animal calls—and noting when those animals go silent—could reveal the arrival of poachers. In 2026, Rainforest Connection will roll out this approach to reserves in Thailand, Jamaica, and Romania by building a unique model for each environment, trained on thousands of hours of audio and verified using camera traps. “We have a lot of eyes and ears in the forest already, all of which are aware and reacting to each other and to new stimuli,” White says.

For the rest of us, Rainforest Connection’s unfiltered stream has another use: an app where you can listen to the livestream from the Ecuadorian rainforest, taking in the complete soundscape of birdsong, frog chatter, and cicada chirps.

Matthew Ponsford is a freelance reporter based in London.