Over the past 50 years, lion numbers have decreased by three-quarters. Only 20,000 to 40,000 of these majestic big cats survive in the wild today. A third of lion deaths are a result of poaching, and even where lions are killed in retaliation over livestock predation, in many cases their body parts are harvested for sale.
Wildlife crime investigators face a big handicap when dealing with confiscated wildlife products. Sifting through dismembered remains — claws, bones, teeth — it is hard to say where they originate from.
To trace lion parts to their source populations, researchers at the University of Illinois Urbana-Champaign developed a web tool, the Lion Localizer, which uses DNA testing to pinpoint the geographic source of contraband lion parts.
“Currently, the origin of most lion products is unknown,” said Rob Ogden, director and co-founder of TRACE Wildlife Forensics Network, a partner in the Lion Localizer project. The U.K.-based nonprofit, which supports the application of forensic science in wildlife law enforcement and works in at least a dozen African countries, is trying to change that.
Barring a small population in India, these big cats (Panthera leo) are only found in Africa. Technically, there are two extant lion subspecies: the northern lion (P. l. leo) and the southern lion (P. l. melanochaita). The former includes populations in Asia and those in Central and West Africa, while the latter includes lions in Southern and East Africa.
DNA samples from confiscated parts are already used to identify species. This is key because to prosecute wildlife criminals, it’s necessary to show the contraband comes from protected wildlife. To pinpoint which population of a particular species takes investigations a step further. It may not directly contribute to proving illegality, but it deepens forensic intelligence into how the wildlife trade operates — knowledge that can aid conservation and management efforts.
While the East African lion population numbers in the thousands, fewer than 500 lions remain in the wild in West Africa. “The West African lion population is tiny, and it’s really, heavily threatened. We cannot afford to lose any,” Ogden said in a statement. “If a product is coming out of East Africa, then it might not be so critical in terms of population numbers, although law enforcement still needs to know about it.”
In a paper on the Lion Localizer in the Journal of Heredity, its creators called the tool a “valuable resource for combating lion poaching, by rapidly identifying populations that are newly targeted, or that are being targeted most aggressively by poachers.”
The DNA of individuals belonging to a species is nearly identical, but there are differences. These variations in their genetic code can distinguish one population from another of the same species.
Users of the Lion Localizer need to extract and sequence a slice of cytochrome b, a region of the mitochondrial DNA (mtDNA). Once they input that sequence in a web form, the tool compares it against fragments of mtDNA in a database. This repository includes sequences from samples collected at 146 sites in 24 countries (African nations and India), which yielded 21 distinct haplotypes or genetic markers that are inherited together.
This set of markers link individuals in a particular geography. Offspring inherit mtDNA only from their mothers. For species like lions, because lionesses don’t disperse far from their natal lands, certain haplotypes can be tied to a geographic area.
“Various researchers who had published scientific papers on lion genetics, and their published mitochondrial DNA sequences were incorporated into the Lion Localizer database,” said Alfred Roca, who teaches courses on conservation and population genetics at the University of Illinois at Urbana-Champaign and is one of the principal architects of the Lion Localizer.
Roca described how Ogden at TRACE approached them with the proposal to build a tool on the lines of another one, Loxodonta Localizer which Roca and his team developed for elephant parts, particularly ivory.
In 2018, TRACE gathered top experts working in lion genetics across Africa and representatives from enforcement agencies in Pretoria, South Africa, for a workshop. “They all had different parts of the jigsaw, but they weren’t necessarily seeing the bigger picture,” Ogden said. To see the bigger picture of the illegal trade in lion parts meant pooling their scientific expertise so something like the Lion Localizer could exist.
At the Pretoria meeting, several ideas for a traceability tool emerged. The simplest one involved using mtDNA. Inputting the DNA sequence gives a list of locations in Africa sorted by the proximity of the match, starting with sites that yielded a perfect match.
The team ran DNA sequences (for which the geographic location was known from published literature) through the tool to validate the method and checked if they matched.
What makes the tool user-friendly isn’t just the interface. Extracting mtDNA is easier than nuclear DNA (nDNA) because there are multiple copies of it in a cell, unlike nDNA, of which only two copies exist in the cell nucleus.
Sometimes, multiple potential source populations can show up because the haplotype is reported from different regions. There’s also the possibility that further investigations will reveal other areas linked to a reported haplotype that are currently not in the database.
“The Lion Localizer doesn’t have the best geographic resolution, but it can be employed by pretty much anybody, including by all the labs that we’ve helped establish in Africa,” Ogden said.
The tool is meant to aid law enforcement wildlife forensics and conservation efforts, which is already happening with the elephant localizer. “There are forensics labs, for example, in Malaysia and the USA, using the tool [Loxodonta Localizer] to examine where their confiscated ivory is being poached within Africa,” Roca said.
Vivienne Williams, a wildlife trade expert at South Africa’s University of the Witwatersrand, who was not involved in the research, told Mongabay that her team hadn’t tried the lion tool yet but planned to do so next year to investigate products used in traditional African medicine.
Within Africa, lion parts are used in traditional medicine or for ceremonial purposes, but domestic use is a small fraction of the overall trade. Most of the illicit trade feeds demand from outside the continent. Lion parts are in high demand in China and Southeast Asian countries like Laos and Vietnam.
However, using a tool like Lion Localizer is problematic when the trade originates in a country like South Africa, which authorized the export of captive lions and their parts in 2016. The controversial policy is facing legal challenges in the country. But by 2019, more than 3,000 lion skeletons and carcasses had already made their way from South Africa to Asian countries. According to Williams, research shows that DNA profiles of wild lions from a protected area like Kruger National Park aren’t easily distinguishable from those of captive lions in South Africa.
Use of forensics in crime investigation, even human crimes, is still relatively nascent in many African countries. TRACE is working toward improving DNA profiling by developing technologies that use nuclear DNA material. Part of the effort is to enhance lab capacities to extract these samples. “These techniques take longer to develop. They’re not as readily applicable in countries where the investigations are taking place,” Ogden said.
There are other ways the geographic origins of wildlife contraband can be determined without relying on genetics. Chemical investigation of samples, for example, through isotope analysis, can yield information about the geographic region they’re from. Williams said it may also be useful for distinguishing between parts derived from captive animals and those from wild lions.
Au, W. C., Dures, S. G., Ishida, Y., Green, C. E., Zhao, K., Ogden, R., & Roca, A. L. (2023). Lion localizer: A software tool for inferring the provenance of lions (Panthera leo) using mitochondrial DNA. Journal of Heredity. doi:10.1093/jhered/esad072
Coals, P., Loveridge, A., Kurian, D., Williams, V. L., Macdonald, D. W., & Ogden, R. (2021). DART mass spectrometry as a potential tool for the differentiation of captive-bred and wild lion bones. Biodiversity and Conservation, 30(6), 1825-1854. doi:10.1007/s10531-021-02170-2
Turner, J., & Wels, H. (2020). Lion conservation and the lion bone trade in South Africa: On CITES, shifting paradigms, “sustainable use” and rehabilitation. The Oriental Anthropologist: A Bi-annual International Journal of the Science of Man, 20(2), 303-314. doi:10.1177/0972558×20952967
Sahajpal, V., Mishra, S., & Bhandari, D. (2021). Forensic analysis in wildlife crime cases: Microscopy, DNA profiling and isotope analysis. In Forensic Analysis — Scientific and Medical Techniques and Evidence under the Microscope. IntechOpen. doi:10.5772/intechopen.98252
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This article by Malavika Vyawahare was first published by Mongabay.com on 13 December 2023. Lead Image: Only 20,000 to 40,000 of the majestic lions survive in the wild today. Image by Ansie Potgieter via Unsplash (Public domain).