If you ask a kindergarten class to draw a rhinoceros, you’ll probably get an amusing variety of artistic renditions. One feature, however, will likely remain constant: a majestic horn adorning its head, defining the rhino's distinct silhouette.
Yet, in the wild, this iconic horn is disappearing – faster than rhinos in some cases.
In the ongoing battle to protect endangered rhino populations from poaching, conservationists employ a controversial practice known as “dehorning.” This process removes the rhino’s valuable horn, and the poachers' incentive to hunt them.
Anecdotally, dehorning has reduced the number of rhino killings in certain reserves, according Vanessa Duthé, a South African Ph.D. candidate at the University of Neuchâtel in Switzerland who specializes in black rhino conservation. But controversy still surrounds the practice and the potential consequences of dehorning.
Black rhinos, one of two African rhino species living today, are listed as critically endangered by the International Union for the Conservation of Nature (IUCN).
Their cousins on the continent, white rhinos, are faring better, although their “near threatened” status is jeopardized by declining populations.
Why Are Black Rhinos Endangered?
These giants of the savanna have been decimated by poaching – the killing of individuals for their horns – since the 1800s. In the latter half of the 20th century, black rhino populations decreased by 96 percent. By 1993, only about 2,300 remained in the wild.
European colonizers dealt the first major blow to black rhinos during the 1800s, by hunting them for sport and trophies at rates much faster than they could reproduce.
Today, rhino horns remain a sign of wealth and status in some parts of the world. They are also a highly controversial component in traditional Chinese medicine, despite a lack of evidence for any real medicinal properties.
These activities have pushed demand for rhino horn to unsustainable levels and fostered a profitable black market trade, with prices soaring up to $65,000 per kilogram (2.2 pounds).
Impact of Rhino Poaching
While poaching has been declining and black rhino numbers are trending upward, poaching remains the deadliest threat to black rhinos today, according to the World Wildlife Fund. The impact of this poaching also extends far beyond the loss of individual animals by leaving an ecological role unfilled.
Black Rhinos and the Ecosystem
As “ecosystem engineers,” rhinos play a central role in maintaining the health of their habitats.
Black rhinos use their hooked lips to munch on trees and shrubs, and their behemoth bodies, which can weigh in at nearly 3,000 pounds, trample soil and plants.
Rhinos also draw tourists, making them a valuable revenue stream for local economies.
Modern poaching groups are becoming increasingly sophisticated, organized and lethal to both rhinos and the humans protecting them, leaving few options for those working to preserve the species.
How Are Conservationists Helping Rhinos?
To safeguard rhinos from extinction, many conservation groups and game reserves have turned to dehorning, with the hopes that horn removal will disincentivize poachers from killing these charismatic animals.
Meticulous planning and careful execution go into dehorning to ensure a swift and safe procedure.
Like a well-oiled machine, field rangers, veterinarians, researchers, a helicopter pilot and other experts coordinate to find and tranquilize the target animals. Once the rhino is asleep, the team covers its eyes and ears and cuts the horn with a chainsaw a few inches from the base.
“We get a lot of criticism for cutting with a chainsaw,” says Duthé, “but it's the best way, the fastest way [to dehorn].”
What Is the Purpose of Rhino Horns?
Scientists are unsure exactly why rhinos evolved to grow horns.
But, like our fingernails, horns get a lot of day-to-day use. “We see them using [their horns] for foraging,” Duthé says.
Horns can also be used as built-in weapons to settle turf disputes. Males with bigger horns are generally more likely to beat their smaller-horned opponents.
How Does Dehorning Work?
Like your fingernails, rhino horns are made of keratin and never stop growing. As a result, dehorning has to be carried out annually or biannually to remain effective.
Dehorning isn’t cheap either – the procedure can cost anywhere between $620 and $1,000 (USD) for a single animal, according to Save the Rhinos International, a conservation organization with roots in the U.K.
After removal, the remaining stump is filed with an angle grinder to smooth jagged edges and ensure the horn grows back properly. The team then evacuates the area and the veterinarian allows the newly hornless, and likely grumpy, rhino to wake up. The whole procedure can be done in just 20 minutes.
Is There a Downside to Dehorning Rhinos?
Despite its relative success in reducing poaching rates, dehorning is not without its drawbacks.
For starters, dehorning does not automatically prevent rhino killings.
Because not all of the horn is removed, there is still value for poachers to exploit. There have also been cases of poachers killing dehorned rhinos without taking anything of value, potentially to avoid accidentally tracking a hornless rhino.
Dehorning has also been linked to changes in rhino behavior, according to a recent study led by Duthé and published in Proceedings of the National Academy of Science.
Decrease in Rhino Ranging
In comparing the area used by rhinos going about their daily activities, also known as a “home range,” Duthé and colleagues found that the home ranges of dehorned rhinos shrunk to almost half of their original size.
While the full implications of this reduction in space use by dehorned rhinos are murky, this research uncovered a clear impact of dehorning on rhinos.
This finding, however, does not change how Duthé sees dehorning. “It's such a dire situation right now – it's urgent – I don't think we should stop dehorning the [populations] that truly need it,” Duthé says.
Continued monitoring will help scientists know if there are other serious long-term consequences of dehorning. For now though, Duthé and colleagues believe the benefits of dehorning outweigh the risks.
“At the end of the day,” Duthé adds, “A weird rhino is better than a dead rhino.”