Rhinoceros are magnificent creatures with a body mass of around 2 metric tons and can run up to around 50 kilometers per hour. In Africa, they have been hunted by poachers for a very long time and nearly escaped extinction. Rhinos are killed for their horns, which are typically used in fake treatments in alternative medicine or used as decorations of daggers. Because of their rarity, air of exclusivity and bought by desperately sick people, it can fetch a massive price. The trade is largely being run by international crime syndicates and sold in east Asia.
Now, scientists and the criminal justice system is fighting back using DNA databases to match individual rhino horns with documented cases of rhino poachings. A recently published paper showed that this DNA database has been used in over 100 cases that have led to criminal convictions. In some cases, the prison sentences have been several years. However, it is by no means a perfect solution, as only a fraction of reported cases lead to convictions. But it is a start.
Why are Rhinos killed for their horns?
There are several reasons for why people pay large sums of money to obtain rhino horns. It is used as a fake treatment among alternative medicine proponents in parts of east Asia and for to make dagger handles in parts of the Middle East. They are not cheap and one horn can cost 60 000 USD per kilogram on the black market. This means that the financial gain from poaching is massive, particularly for the dealers who buy it from poachers and sell it to customers. This tragedy is not just happening to rhinos, but to many other large animals, including antelopes, tigers and elephants.
The number of rhinos killed by poachers is staggering. For South Africa, there were 13 rhinos poached in 2007. This figure rose sharply to 448 in 2011 and spiked to 1214 in 2014. Since they, it has declined somewhat, but this is primarily because there are so few rhinos left that it is getting harder and harder for poachers to find targets. For some species of rhinos, such as the northern white rhino, there are only three individuals left that are under around-the-clock protection from armed guards. None of them can breed in nature, so the species is effectively extinct. However, scientists are trying to use in vitro fertilization and advanced molecular biology tools to create fertilized eggs that can be carried by surrogate rhinos and potentially prevent the species from going extinct forever.
Selling rhino horns is, of course, illegal and the laws are being more strictly enforced in recent years, yet there seems to be difficult to put an end to the poaching due to the enormous sums of money involved and the rhino horn trade being run by organized criminal syndicates operating on the international stage.
What can a Rhino DNA database do?
Rhinos are animals and have their own unique individual DNA profile just like humans. So that means that, with the possible exception of identical rhino twins, DNA isolates sold from the horns sold on the black market to the poaching of specific individuals. This idea can be extended by taking DNA samples (from short tandem repeats) from thousands of living rhinos and put it in a database. This database, called Rhinoceros DNA Index System (RhODIS), currently consist of a panel of 23 STRs and 3968 individuals from both black and white rhinos.
When a new rhino horn is discovered, it is subjected to DNA testing and checked against the rhino DNA database. This provides additional evidence to support a criminal conviction, and researched published in early 2018 by Harper and colleagues in the journal Current Biology shows that it has been instrumental in getting some of those convictions and also harsher sentences. So far, the database has been used in at least 120 criminal cases. Sentences for a selected sample of convictions in the paper ranges from 15 months to close to 30 years in prison.
Thus, this kind of STR database shows the power of forensic DNA evidence in criminal cases involving rhino poaching in much the same way that DNA evidence can be crucial in many violent crimes involving human victims. It is just the extension of this standard forensic method to rhinos. If enough cases accumulate, it may be possible to make geographical profiles to identify hot spots where specific groups of poachers are especially active and discover new trafficking routes.
What are some of the future challenges?
This method is, however, far from a magic bullet that will solve the problem of rhino poaching. Since 2010, a total of 5800 criminal cases involve rhinos have been submitted, but only 120 have led to convictions. As a proportion, this is only about 2% of cases.
It is also tricky to draw stringent causal conclusions between the existence of the database and convictions, but we know DNA evidence is effective and there seems to be a tendency for poachers to be more reluctant to appeal if there is hard DNA evidence against them.
The key to destroying rhino poaching is to target the international crime syndicates that are behind it. This requires that law enforcement are as active in other parts of the world that are key to rhino horn trafficking as they are in South Africa.
Finally, there needs to be a cultural change in the environments were buyers reside. Do not buy rhino horns or products made with rhino horns. Do not buy daggers that contain rhino horns and do not use fake treatments from alternative medicine that involve rhino horns. There needs to be more stigma and shame attached to using rhino horns and it should be viewed with the same level of ridicule as eating nail clippings.
Because, after all, rhino horns are made of keratin, just like human finger nails. You would never eat your own finger nails thinking that it would treat medical conditions, would you? There are probably some proponents of various fake treatments that would actually recommend this, but hopefully most reasonable people would realize the futility of this approach to health and the treatment of medical conditions.