DNA analysis is helping authorities catch pangolin poachers

Africa’s white-bellied pangolin (Phataginus tricuspis) hold the unfortunate title of being the most trafficked mammal in the world as well as being endangered.

Many of these white-belied pangolins end up in China, their scales being used for traditional medicine, but their range is across sub-Saharan Africa, so determining exactly where they came from is no easy task for anti-trafficking authorities.

“Given the extensive geographic range of white-bellied pangolins and many other trafficked species, identifying poaching hotspots at a scale that is useful to law enforcement is crucial for conservation efforts,” say researchers who have tried to genetically map poached pangolins to identify their source, and therefore poaching hotspots.

“Without genetic data to reveal the true geographic origins of poached animals or products, seizures by law enforcement agencies offer limited information about their sources.”

The researchers outlined their results in a new paper, published in Science.

Firstly, the white-belied pangolins are located only in Africa. They are not to be confused with the Guangdong Pangolins which might have been the species host for SARS-CoV-2.

In the case of the white-belied pangolins, they set out to genetically map where the pangolins were being taken from, analysing 111 samples, and 643 scales, to create a map of location, as well as time.

The team started out with 551 samples of blood, muscle and scales where the location of the wild pangolin was known. Looking at 96 individual changes to the genome, the international team of researchers could then construct a map of the subgroups, spreading from Guinea across to parts of the Democratic Republic of the Congo.

Pangolins fig1
Map of genomically identified white-bellied pangolin population clusters. Credit: Tinsman et al., Science, 2023.

“Network mapping of African pangolin seizures identified Nigeria as the highest-volume transit hub in Africa, where traffickers amass pangolin scales before shipping them overseas,” the researchers write.

“By contrast, our genetic assay results show that only 4.2% of pangolins shipped from Nigeria originated there. Most of the pangolins in our samples that transited through Nigeria originated in southern Cameroon, mainland Equatorial Guinea, and Gabon.”

Because the team also had access to when shipments were seized – from 2012 to 2018 – they could also map changes where pangolins were being poached over time.

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Changes in pangolin poaching over time. Credit: Tinsman et al., Science, 2023.

“Testing seizures confiscated over just 7 years (2012–2018) enabled us to detect changes in the origins of trafficked pangolins,” the researchers write in their paper.

“Early on, poaching activity was confined to West Africa before shifting to Central Africa more recently. These changes in trafficking patterns could represent a response to increased enforcement; declining pangolin populations in West Africa; taking advantage of new, convenient trade routes, or a combination.”

This also means that more research like this will be needed, as pangolin poachers continue to shift locations. “Compared with traditional law enforcement investigations, the genetic assay reduces the time lag between intercepting wildlife products, tracing an international supply chain to its origins, and reactive enforcement,” the researchers conclude.

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