Dehorning Rhinos

[Flutterby]

[Lisbeth]

Rhinos’ Horns Were Cut to Thwart Poachers. After, They Didn’t Go Out Much.

New research shows a conservation strategy can disrupt the animals’ social networks.


Trimming the horn of a tranquilized female black rhino in South Africa.Credit...Kim Ludbrook/EPA, via Shutterstock

By Rachel Nuwer
Published June 12, 2023
Updated June 14, 2023

Black rhinos are the junkyard dogs of African rhinos. They’re not the biggest species on the continent, but they’re known for aggressively patrolling and defending their territories and are quick to charge any person, vehicle or other rhino they perceive as an intruder.

One of the keys to that behavior, it turns out, appears to be their horns.

Research published on Monday shows that black rhinos that have been dehorned in an attempt to thwart poachers engage in significantly fewer interactions with other rhinos and reduce the size of their home ranges.

“It’s definitely disrupting their social networks,” said Vanessa Duthé, a doctoral candidate in conservation biology at the University of Neuchâtel in Switzerland, and lead author of the findings, which appeared in the Proceedings of the National Academy of Sciences.

“It’s sort of like if you put a muzzle on a dog,” Ms. Duthé said. “They’re not so sure of themselves anymore. They’ve lost their main defense and their confidence.”

Rhinos that have been stripped of their main armament, their horn, seem to feel more vulnerable, Ms. Duthé said. This vulnerability is exhibited through their diminished appetite for exploring and for engaging in conflict with other rhinos.

The research does not address whether black rhinos’ “very strong response” to dehorning has an overall positive or negative effect on the species, Ms. Duthé added, such as whether it will result in genetic changes over time by shifting reproductive dynamics, or alter the number of animals that a given landscape can support.

Dehorning has become increasingly common over the past decade in Southern Africa as a means of trying to deter poachers from killing rhinos for their horns, which can be valued more than diamonds or gold on the black market in Southeast Asia.

Dehorning is a painless procedure in which veterinarians first sedate a rhino. They blindfold the animal and insert earplugs, then use a chain saw to cut off the top of its horn, but only the section that does not contain nerves. The base of the horn is then sanded down. The entire process takes no more than 20 minutes. Like fingernails, rhino horns grow back with time and animals are usually dehorned once every 18 months.

Despite the prevalence of this practice, researchers did not know until now what effects, if any, dehorning had on rhino behavior and survival.

More ornery than white rhinos, their larger and more populous cousins, black rhinos are a critically endangered species: Only 5,500 to 6,000 individuals remain, 36 percent of them in South Africa. Ms. Duthé and her colleagues analyzed 15 years of data tracking the movements of 368 of those animals across 10 South African wildlife reserves. Before 2013, none of the black rhinos included in the study had been dehorned, but by 2020, 63 percent had.

The researchers found that dehorning did not increase the chances that a rhino would die from causes other than poaching. However, dehorned animals’ home ranges shrank by an average of 45.5 percent, although those figures varied by individuals. For example, one male, Hamba Njalo, lost 27 percent of his territory, leaving him with 9.25 square miles, while another male, Xosha, lost 82 percent of his, leaving him with just under 3 square miles.

Dehorned individuals were also 37 percent less likely to engage in social interactions, especially those between males.

“The study is robust and good science, with long-term data and a large set of observations,” said Sam Ferreira, a large-mammal ecologist at the International Union for Conservation of Nature’s African Rhino Specialist Group, who was not involved in the research. “The results highlight important unintended consequences when seeking to deal with indirect approaches such as dehorning to address societal pressures on rhinos,” including poaching.

Rhino poaching has subsided from its peak in 2015, when 1,349 animals were killed out of a total African white and black rhino population of around 22,100. But the situation today remains “really critical and urgent,” Ms. Duthé said, with more than 548 rhinos poached across Africa last year.

While the rise of dehorning has correlated with a decline in the number of rhinos killed, a mix of economic, social and security factors also affects poaching. “No one has come to the conclusion yet” as to whether dehorning is effective, Ms. Duthé said.

But even with all the unknowns, and with the new results pointing to the impacts on rhino behavior, dehorning still seems to be a valuable conservation tool that “in some instances is needed,” Ms. Duthé said. This is especially the case in reserves that cannot afford to increase other security measures for animals.

Michael ’t Sas-Rolfes, a conservation economist at Stellenbosch University in South Africa who was not involved in the research, said that dehorning is not ideal, but is “a somewhat desperate measure.”

“It’s all very well to be in favor of ideal solutions, but we must be pragmatic in the short run to ensure that rhinos survive the ongoing poaching onslaught,” he said. “The fact that dehorning is so widely employed now is indicative of how serious the poaching problem remains.”

A correction was made on June 13, 2023: Because of incorrect information supplied by the photo agency, a picture caption with this article misidentified a group of rhinos in Kenya. The animals pictured were white rhinos, not black rhinos. The photo has been removed.

A correction was made on June 14, 2023: An earlier version of this article stated incorrectly the amount of territory lost by two rhinos after they were dehorned. Hamba Njalo lost 27 percent of his territory and was left with 9.25 square miles, not just over two square miles. Xosha lost 82 percent and was left with just under 3 square miles, not 8.5 square miles.

[Richprins]

Very interesting!

Perhaps a good side effect is that the males do not kill each other that much, which they are prone to do...

[Lisbeth]

DEHORNED RHINOS


A new study suggests dehorning can negatively impact black rhinos social behaviours

We have a rhino-poaching crisis on our hands, and dehorning has emerged as one of the vital strategies in curbing incidents of poaching. But for years, many have wondered what impact dehorning has on the individual rhino that has faced the chainsaw. A new study suggests concerning implications for black rhinos.

Click on the the title to read the story

[Richprins]

[Lisbeth]

Desperation dehorning under way to curb runaway KwaZulu-Natal rhino poaching


A major operation has begun to dehorn large numbers of rhinos in the historic Hluhluwe-iMfoozi Park in KwaZulu-Natal. (Photo: Ezemvelo KZN Wildlife)

By Tony Carnie | 16 Apr 2024

In a drastic move to curb rampant rhino poaching in KwaZulu-Natal, the provincial conservation agency has embarked on an immediate programme to cut off the horns of hundreds of the animals in KZN’s largest rhino reserve.
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Until recently, the Hluhluwe-iMfolozi Park — proclaimed in 1895 to preserve the world’s last remaining southern white rhinos — was one of the few remaining state-owned sanctuaries in South Africa where visitors could still see significant numbers of rhinos with their iconic horns intact.


Until now, the 96000ha Hluhluwe-iMfolozi Park was home to one of the last significant populations of rhinos in a South African public reserve where rhinos still have their horns intact. (Photo: Ezemvelo KZN Wildlife)

That’s changing. A new dehorning programme, with support from the WWF conservation group, was announced on Tuesday by Ezemvelo KZN Wildlife chief executive Sihle Mkhize.

This follows the killing of 325 rhinos in the province last year, with more than 300 of the animals poached in the 96,000-hectare Hluhluwe-iMfolozi Park alone. The KZN killings accounted for nearly 65% of the 499 rhinos killed nationwide in 2023.

Mkhize said the dehorning operation began on 8 April, in a province where poaching rates had tripled over the past three years.

“It is with a heavy heart that the organisation has decided to dehorn,” Mkhize said. “Rhino dehorning goes against the grain of what we stand for, but the persistent threat posed by poachers has necessitated more drastic measures to protect our rhinos.”

Acknowledging that dehorning was costly and required repeated “trimming” operations every 18 to 24 months as the horns regrow naturally, Mkhize thanked WWF for its “pivotal financial support”.

Read more in Daily Maverick: Two out of three SA white rhinos now in private hands while poachers decimate KZN herds

The agency has been under pressure to follow the example of the Kruger National Park and other government and private sector reserves to dehorn rhinos as one of several strategies to reduce poaching.


Conservation staff use a chainsaw to remove the front horn of a rhino in Hluhluwe-iMfolozi Park. The move follows similar desperate measures in other reserves across the country – including Kruger National Park, where almost 70% of the rhino population was reported to have been dehorned during the 2022/2023 reporting period. (Photo: Ezemvelo KZN Wildlife)

While dehorning has been promoted in several quarters as a drastic but “unavoidable” measure, the latest decision is controversial at both a symbolic and ecological level. This is because their horns are rhinos’ primary defensive tool, while their removal robs tourists of the opportunity to see rhinos in their natural state with horns intact.

The strategy was first adopted in Namibia and Zimbabwe in the late 1980s and early 1990s as a response to the continent-wide poaching crisis and has since been adopted in most of southern Africa.

‘Absolute last resort’

Former Ezemvelo regional ecologist Dr Peter Goodman noted that it was a sad day for rhino conservation and he questioned the wisdom of resorting to such desperate measures.

Goodman acknowledged that dehorning was likely to result in a significant reduction in poaching in the short term — if the entire rhino population in Hluhluwe-iMfolozi was dehorned simultaneously.

However, he noted, the strategy would simply displace poaching to other state and private reserves where rhinos were not dehorned or where dehorning had been discontinued.

He noted that East African rhino range nations viewed dehorning as an “absolute last resort”.

“Kenya, Tanzania and Rwanda are not dehorning their rhinos, yet their populations are still growing.”

“Sadly, the elephant in the room is the lack of law enforcement, political will and legal support. We still see courts releasing rhino poachers on R5,000 bail — and two weeks later they are back poaching in the same reserves.

“The real problem is syndicated crime. This problem is all about security … and corruption. If you have bad actors, the poaching is not going to stop,” Goodman said, noting that only about 80% of a rhino’s horn could be removed safely without damaging the horn growth plate.

As a result, the stumps left behind after dehorning remained economically attractive from a poacher’s perspective.

“I believe we should be focusing instead on sorting out our legal system. We also need more dedicated, honest cops and more effective public-private partnerships among landowners to solve the crisis together.”

Goodman — who was seriously gored by a black rhino in Mkhuze game reserve in 1992 and spent nine days in hospital before recuperating at home for several weeks after surgery — said: “We know already who the main people are. We see politicians… We see rhino horns being smuggled out the country in consular bags.”

Nevertheless, South African National Parks reported last year that nearly 70% of Kruger’s rhino population was dehorned during the 2022/2023 reporting period.

Guardianship strategy

Commenting on the latest KZN dehorning operation, WWF South Africa CEO Dr Morné du Plessis said: “A decision to dehorn is never taken lightly and is only one of a wide range of interventions which together seek to simultaneously remove the potential reward of rhino poaching while increasing the likelihood of being caught.

“The province of KZN has played a critical role in rhino conservation in Africa, which is why we are committing resources towards supporting the authorities in their efforts to protect rhinos. Beyond the dehorning programme, we will also be supporting Ezemvelo in its broader efforts to implement the Ezemvelo KZN Guardianship Strategy for Rhinoceros.”

Read more in Daily Maverick: More than 60% of rhino killings now in KwaZulu-Natal as poachers shift from ‘battered’ Kruger Park

Ezemvelo also committed itself to implementing the recently approved guardianship strategy, which would include:

• Investing nearly R11-million to erect a smart fence to cover a significant portion of the park boundaries where poaching levels are high;

• Financial support of about R40-million by the national Department of Forestry, Fisheries and the Environment to extend the area covered by the smart fence around the park;

• Increasing the numbers of field rangers from 45 to 88;

• Introducing integrity testing among frontline staff;

• Installing trackers in all vehicles;

• Improving relations with adjacent communities;

• Additional helicopter hours and night vision capability; and

• The recent appointment of former section ranger Sthembiso Ndlovu as the senior manager for rhino protection.

DM

[Lisbeth]

Better late than never

[Richprins]

It is a pity but they have no choice.

[Lisbeth]

Hornless hope: is rhino dehorning the most effective tool in saving the species?

Posted on June 18, 2025 by teamAG in the Decoding Science post series.



In the world of conservation, few animals carry the burden of celebrity quite like the rhino. The rhino is a walking target: its horn is falsely believed by a distant market to cure cancer and other ailments, and is also considered a status symbol in these markets. And despite decades of boots on the ground, drones in the sky, and millions of dollars spent on anti-poaching, the grim scoreboard of poaching keeps ticking up. But what if the best way to save a rhino is to cut off its horns? Is a chainsaw the most effective tool in saving rhinos? A new study on rhino dehorning suggests so
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A team of scientists and conservationists from southern Africa has just delivered a jarring research report on rhino protection. By pooling expertise and data across multiple reserves, the report aimed to provide a clearer picture of how dehorning influences rhino behaviour, ecology, and conservation outcomes.

Their study, published in Science, lays it out in stark terms: Dehorning rhinos by surgically removing their horns – a painless procedure – was the only intervention that consistently reduced poaching across 11 major reserves in the Greater Kruger ecosystem (a stronghold that protects 27% of all of Africa’s rhinos). And the strategy proved dramatically effective.


A dehorned black rhino in Greater Kruger

The numbers game: guns, dogs, and dollars

Over a seven-year period (2017–2023), 1,985 rhinos were killed in the very areas that are supposed to be the last bastions of safety. That’s around 6.5% of the population annually – a slow bleed in the life expectancy of a species. This, according to the Kuiper et al study spearheaded by the Greater Kruger Environmental Protection Foundation (GKEPF). To better understand the long-term impacts of dehorning on rhinos, GKEPF established a collaborative research project involving reserve managers, field rangers, and scientists from the University of Cape Town, Nelson Mandela University, Stellenbosch University, and the University of Oxford. This multi-institutional effort was further supported by key conservation bodies, including South African National Parks (SANParks), WWF South Africa, and the Rhino Recovery Fund.

The project was initially conceived by those working on the frontlines of rhino conservation and was driven by Sharon Haussmann, CEO of GKEPF, who tragically died less than a week before the study results were published (leaving the researchers to dedicate this project to her).

Recognising the need to assess the effectiveness of their significant investments in anti-poaching tools, such as tracking dogs and AI-enabled surveillance, GKEPF set out to evaluate whether these interventions were truly making an impact.

To combat rhino poaching, reserves poured roughly US$74 million into traditional antipoaching tactics: ranger teams, canine units, fences, infrared cameras, and even polygraph tests (5,562 of them). This resulted in over 700 poacher arrests. Unfortunately, this high-tech, high-cost effort showed no clear statistical effect on reducing poaching (although one could argue that, without these interventions, numbers could’ve soared even more).

Teams on the ground are up against a giant: organised criminal syndicates move faster than the justice system. Arrested poachers walk free. And insiders often leak information, for example, through the advance notice of patrol movements. High-risk poaching remains prevalent, driven by “horn demand, wealth inequality, embedded criminal syndicates, and corruption,” says the study. In this world of wildlife crime, enforcement is a leaky bucket. So, what actually worked?


A recently dehorned white rhino and calf

The rhino in the room

Enter rhino dehorning: a blunt, counterintuitive solution. By removing the primary motivation for the kill – the horn – experts are dramatically reducing the reward for the crime.

Across the eight reserves that implemented rhino dehorning (dehorning 2,284 rhinos in total), poaching plummeted by an average of 78%. The data showed it wasn’t just a correlation; it was a causal, abrupt change. Rhino killings didn’t slowly decline: they dropped off immediately after the horns were removed. No other intervention came close.

Even at the level of individual rhinos, the difference was staggering: horned individuals had a 13% chance of being poached annually, compared to just 0.6% for their dehorned counterparts. On average, dehorning all rhinos on a reserve reduced poaching by ~75% from pre-dehorning levels.

Significantly, the cost of this intervention weighed in at a low US$570 per rhino operation to conduct the dehorning, less than 2% of the total antipoaching budget. In a world of limited conservation funding, lower-cost solutions are imperative.


Dehorning all rhinos on a reserve reduced poaching by ~75% from pre-dehorning levels

The fine print on rhino dehorning: not a silver bullet

Of course, rhino dehorning is not without caveats. Rhino horns regrow, meaning dehorning must be repeated every 18 months. In some areas – particularly Kruger National Park – even dehorned rhinos were still poached. In total, 111 dehorned rhinos were still poached during the study period (107 of these were poached in Kruger NP between 2022–2023). This is because up to 15cm of horn remains after the procedure, as veterinarians must leave a protective layer to avoid damaging the sensitive growth plate at the base of the horn. Even a stub of horn holds black-market value, and Kruger National Park’s porous border with Mozambique offers easy syndicate access. Furthermore, only between 50–55% of rhinos in Kruger National Park are dehorned.

Moreover, there’s the philosophical and ecological question: What does it mean to keep a rhino hornless? So far, research suggests little negative impact on survival, but the long-term consequences, particularly behavioural ones, are still murky. One study suggested that dehorning black rhinos significantly reduces their home range size and weakens social interactions, especially between males. These behavioural changes could have long-term hidden impacts on reproduction, territory use, and population dynamics.

Another consideration is that, as evidence suggests, dehorning rhinos in one area may simply shift poaching pressure to regions where rhinos remain horned, as seen in Hluhluwe-iMfolozi Park in 2022, South Africa’s second-largest rhino stronghold. However, in 2024, Hluhluwe-iMfolozi embarked on a major dehorning operation which also saw a reduction in rhino poaching.


A dehorning operation in Greater Kruger

Rethinking the war on rhino poaching

While this study suggests more effective impacts from rhino dehorning, it doesn’t argue against traditional interventions, but rather calls for a multi-pronged approach. Ranger patrols, tracking dogs, community support, and aerial surveillance still matter, particularly as a backup plan. But if the goal is to stop poaching before the bullet is fired, then removing horns might work better than pursuing transgressors.

And perhaps that’s the real takeaway: conservation is messy. It’s not always romantic. Sometimes, it involves a chainsaw. But if the trade-off is between a hornless rhino and no rhino at all, then the choice becomes heartbreakingly simple.

Reference:

Timothy Kuiper et al. (2025). “Dehorning reduces rhino poaching“. Science 388, Issue 6751, 1075-1081. DOI:10.1126/science.ado7490.