A South African game reserve called Sabi Sand is taking extreme steps to combat rhino poaching: they're injecting a mixture of poison and indelible pink dye into the horns of live rhinos.
According to officials, the injection doesn't cause any harm to the animals, but anyone who eats the horn once it's ground into powder will get "seriously ill," and the dye will help authorities track poached horns.
It's a radical step. But officials at the reserve claim it's necessary: up to 1,000 rhinos may die this year alone because of poaching. More than 200 have been killed in South Africa since the start of the year.
Over the past 18 months, Sabi Sand has injected the dye and poison mixture into more than 100 rhinos' horns. The hope is that by making the horns unfit for eating, poachers will decide that rhinos from Sabi Sand aren't worth targeting.
"Everything we've tried has not been working and for poachers it has become a low-risk, high-reward ratio," Andrew Parker, chief executive of the Sabi Sand Wildtuin Association, told the Guardian.
"By contaminating the horn, you reduce the reward and the horn becomes a valueless product."
As for tracking, airport scanners will be able to detect the pink dye even if the horn has been ground into powder, which officials hope will prevent poachers from transporting rhino horns through airports in any form.
The poison may not be deadly to people, but it sounds pretty nasty: "It'll make [people] very ill - nausea, stomach ache, diarrhea," Parker said. It's made from parasiticides that are normally used to control ticks on horses, sheep and cattle.
But thanks to the pink dye, Parker says it's unlikely anyone would ingest the poisoned horn accidentally. "It will be very visible, so it would take a very stupid consumer to consume this."
Tom Milliken, the rhino programme coordinator for wildlife trade monitoring network Traffic, said he wonders "if unscrupulous dealers in these markets will not simply employ some means to 'bleach' them back to a normal appearance and continue raking in these high profits."
He also suggested that the Sabi Sand initiative might help deter poachers in a contained environment like the reserve, but it "is impractical in situations involving free-ranging animals in large areas, places like Kruger national park with 20,000 sq km," he said.
"Thus, like dehorning, it probably has the effect of displacing poaching intensity to other areas, not stopping it altogether."
South Africa National Parks supports the idea, but a spokesperson said it would be "virtually impossible" to apply the process to all the rhinos in national parks, as they don't have the resources.