Can dyeing rhino horns and ivory pink prevent poaching?

Recently, a story has been circulating on the Internet: African animal protection organizations use a chemical dye to dye rhino horns and ivory pink ; this dye is difficult to wash off and has a certain degree of toxicity. As a result, ivory and rhino horns have no commercial value and cannot be used as medicine.

This does sound like a new idea for protecting elephants and rhinos, but the accompanying picture is too heavily photoshopped .

As early as 2015, this set of pictures was very popular on foreign social networks | Caroline Bosson / Facebook

So is this true?

Yes, but not entirely.

What is the truth?

The technical means mentioned in the story are real. This is a project implemented by the South African animal protection organization "Rhino Rescue Project" around 2012. The substance they injected into the rhino horns is actually a mixture of dye and pesticide .

The idea actually came from the way the group deworms rhinos, believing that insecticides injected into the horns could diffuse through the epidermis and alleviate the discomfort caused by the parasites.

So what if this pesticide is toxic to humans?

After repeated tests, the research team of the "Rhino Conservation Project" finally developed an insecticide that is safe for animals but can cause severe nausea and vomiting in humans. They also placed signs around the reserve to tell poachers that the rhino horns are contaminated and cannot be eaten.

Drilling holes in rhino horns to inject pesticides | Rhino Rescue Project / savetherhino.org

The dye in the mixture is similar to the anti-robbery dye used in banks, and the rhino horns dyed with it, even if ground into powder, will be detected by airport security systems. The organization hopes to be able to combat the transnational smuggling trade.

The only risk during the entire treatment process is the anesthesia step . Subsequent monitoring of the "dyed" rhinos also showed that they were in good health, and pregnant female rhinos during the lactation period also gave birth to healthy calves and secreted milk normally.

What about ivory?

Unfortunately, elephant tusks cannot be treated in this way, so the idea of ​​dyed ivory is a complete myth . This is due to the very different composition of rhino horn and elephant ivory.

The main component of rhino horns is keratin, which is also the material that makes up hair and nails. Unlike the horns of cattle and sheep, rhino horns do not have any bone core, but are made entirely of bundles of tiny keratin tubes - in layman's terms, rhino horns are like a bundle of tightly compressed hair . The "Rhino Conservation Project" hopes that the dye injected into the rhino horns will diffuse through these tiny tubes throughout the horn, thereby "poisoning" the entire rhino horn.

Microscopic morphology and results of rhino horns. The white circles are keratin tubes | Hieronymus TL et al. (2006)

The elephant's tusks are actually specialized incisors, which are made of hard inorganic substances (hydroxyapatite), just like your teeth and mine. It's impossible to dye the tusks with a dye. It's not impossible to paint them with a layer of color (after all, humans do similar things to their own teeth), but since tusks are important tools for elephants, digging, lifting objects, peeling bark... the color will probably wear off in a few days .

The tooth is closely connected to the pulp cavity | Virág A. (2012)

Is it safe to dye rhino horns?

Dyeing rhino horns is indeed a proactive way to combat poaching, but it soon became increasingly controversial .

First, rhinos love to roll in mud pits. The mud forms a protective layer on their skin, preventing insect bites, killing parasites, and keeping them cool. When they roll around, will they be careful not to stain their dyed horns? Rhinos' horns continue to grow; they need to be re-injected with dye every three to four years, and each operation costs $900 . With tens of thousands of rhinos waiting to be saved on the African continent, the cost of this project can be imagined.

Secondly, as mentioned above, there are also great risks in giving rhinos anesthesia . During the entire dyeing process, the rhinoceros will be under general anesthesia for up to 45 minutes. The dosage of anesthetic is not easy to control, and the rhinoceros may not wake up from anesthesia.

Anesthetizing a rhino is a huge challenge | Michal Knotek / pexels.com

Not only that, in 2014, scientists from the South African National Parks Scientific Service and the Veterinary Department conducted a study on the effects of dye injection. They found that the dye only existed around the drill hole and could not completely penetrate the entire horn !

In fact, the assumption behind devaluing rhino horns by “poisoning” them is that consumers will not buy rhino horns for fear of being poisoned, thereby reducing the demand for rhino horns. To achieve this, animal protection organizations need to not only erect signs around protected areas to warn poachers, but most importantly, widely publicize among consumer groups in Asia. But the message that “rhino horns are poisoned” does not seem to have reached the other side of the ocean. Moreover, even if poachers know that rhino horns are poisonous, will they give up huge profits for the health of an unrelated person?

Moreover, since rhino horns are circulated on the black market, it is almost impossible to conduct a " user experience survey " on buyers of poisonous rhino horns to see how toxic they are. Therefore, the assumption of the "Rhino Conservation Plan" was untenable from the beginning.

Customs seized rhino horn and ivory chopsticks | Aaron Tam / AFP

Seeking the best solution

Almost every possible approach has been tried to save elephant and rhino populations.

Cut off rhino horns and ivory

Aren't horns and tusks what poachers are looking for? If they are removed, won't the animal be safe? This method is often used on rhinos.

But for rhinos, since their horns are constantly growing , they have to be sawed off every one to two years, which also faces high costs and anesthesia risks. In addition, in order not to affect the regeneration of the horns, the horns cannot be sawed too close to the roots, so 10% of the horns will still be retained - this is enough for poachers to make a fortune.

Rhino undergoing dehorning surgery | Bernard Dupont / flickr.com

Similarly, although ivory does not regenerate, after sawing off the exposed tusks, one-third of the teeth are still buried in the skull, which will also become a target for poachers.

Despite this, dehorning has achieved some success. For example, in some reserves in Lovell, Zimbabwe, dehorned rhinos have a 29.1% higher chance of survival than those with horns .

Alternatives

In recent years, many scientific research teams have tried to develop artificial rhino horns and allow them to flow into the market (black market) in large quantities , thereby devaluing rhino horns. In 2019, researchers from Oxford University and Fudan University jointly developed an artificial rhino horn made from the tail hair of a rhino's close relative (horse). Whether in appearance, feel, or even microscopic structure, it can be mistaken for the real thing.

However, some conservationists believe that this could provide a safe haven for the illegal trade . If the artificial horns are truly indistinguishable from natural ones, then when poachers confront law enforcement, they could claim the horns are fake.

Microscopic view of real rhino horns (left column) and artificial horsehair rhino horns (right column). They are very similar | Mi R. et al. (2019)

The same debate exists on the legalization of rhino horn and ivory trade. It is difficult to distinguish between legal and illegal, which will bring huge obstacles to law enforcement. Past practice has shown that legalization of ivory has made poaching more rampant .

Anti-poaching reconnaissance

At present, the most reliable way to protect elephants and rhinos is strict anti-poaching reconnaissance . With the advancement of technology, the rangers' reconnaissance methods are becoming more and more efficient. They no longer simply drive around looking for poachers, but put tracking collars on animals to track their whereabouts, locate the location of poaching activities, and even use drones for reconnaissance. At the same time, managers will also identify poaching hotspots through long-term monitoring data and focus on patrolling these areas.

Zimbabwe's anti-poaching unit patrols Bumihills to protect local elephants | Bumihillsfoundation / Wikipedia Commons

However, the Orissa Wildlife Association in India questioned the tracking collars - they spent a huge amount of money to install tracking collars for elephants, but the collars were pulled off by these clever ghosts within a few days...

No matter what kind of protection method is used, there will always be advantages and disadvantages, and it is far from perfect - after all, this is a battle about human nature . Can rationality and care defeat selfishness and greed? Perhaps only if we make real changes on the demand side can we let wild animals see the dawn of hope for their fate.

References

[1] Hieronymus TL et al. J. Morphol. (2006) 267 :1172–1176

[2] Virág AJ Morphol. (2012) 273 :1406–1423

[3] Mi R. et al. Sci. Rep. (2019) 9:16233

Author: Jian Er

Editor: trombonist

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