Genetic evidence can be used to track confiscated rhinoceros horns back to the carcasses they are taken from, according to a study published yesterday (January 8) in Current Biology.

The study highlights nine cases where information from the Rhino DNA Index System (RhODIS), a database that contains DNA samples of around 4,000 animals from black and white rhinoceros populations, was used for the prosecution and sentencing of poachers and traffickers. To date, more than 5,800 rhinoceros crimes have been submitted to the database, and in more than 120 cases, researchers could link poached carcasses to confiscated horns or blood stains on items of evidence. 

 “The majority of cases in which we have been able to make these individual links have led to convictions and, in many cases, significant sentences,” coauthor Cindy Harper of the Veterinary Genetics Laboratory at South Africa’s University of Pretoria, tells ...

This includes the conviction of Simon Ngomane, a rhino poacher who was sentenced to nearly 30 years in prison. The DNA library revealed that two rhino horns belonged to an animal slaughtered in South Africa’s protected Kruger National Park—evidence that helped lead to his conviction in 2017.

For Harper, who began building the database in 2010, its strength lies in the ability to reliably match the unique genetic profile of an animal through samples obtained from body parts such as horns, by using 23 short tandem repeat loci. “Unlike similar work in which genetic databases provide an indication of geographic provenance, RhODIS provides individual matches that, similar to human DNA profiling, is used as direct evidence in criminal court cases,” Harper says in a statement.  

The International Union for the Conservation of Nature classifies black and white rhinos as critically endangered and near threatened, respectively. Throughout the past decade, more than 7,000 African rhinos have been hunted illegally, according to the press release.

Rhinos are slaughtered for their horns, which are prized for both medicinal purposes and as status symbols and are valued at more than $60,000 per kilogram, according to Nature. “That’s like gold cocaine,” University of Washington conservation biologist Samuel Wasser, who was not involved in the study, tells Nature. However, Wasser notes that the database has helped only 2 percent of crimes lead to a criminal case. “It’s not giving you bang for the buck,” he adds.   

 Having DNA evidence might make poachers less likely to appeal against their convictions, but the real issue is enforcement, Rod Potter, a study coauthor and wildlife investigator at the conservation agency Ezemvelo KZN Wildlife in South Africa, tells Nature. “The DNA is showing is all sort of interesting things, but you’ve got to get the police departments to investigate further.” 

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