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Elephant genotypes reveal the size and connectivity of transnational ivory traffickers


Transnational ivory traffickers continue to smuggle large shipments of elephant ivory out of Africa, yet prosecutions and convictions remain few. We identify trafficking networks on the basis of genetic matching of tusks from the same individual or close relatives in separate shipments. Analyses are drawn from 4,320 savannah (Loxodonta africana) and forest (L. cyclotis) elephant tusks, sampled from 49 large ivory seizures totalling 111 t, shipped out of Africa between 2002 and 2019. Network analyses reveal a repeating pattern wherein tusks from the same individual or close relatives are found in separate seizures that were containerized in, and transited through, common African ports. Results suggest that individual traffickers are exporting dozens of shipments, with considerable connectivity between traffickers operating in different ports. These tools provide a framework to combine evidence from multiple investigations, strengthen prosecutions and support indictment and prosecution of transnational ivory traffickers for the totality of their crimes.

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Fig. 1: Geographical span and colour code scheme for ports of containerization used for all consequent figures.
Fig. 2: Temporal progression in the major ports of containerization and their connectivity, based on genetic matches and shared physical evidence between seizures.
Fig. 3: Genetic and physical-evidence matches between tusks in representative ivory seizures containerized in East Africa and all other seizures in our dataset.
Fig. 4: Seizures containerized in West Africa.
Fig. 5: Network of all genetic matches between seizures.

Data availability

DNA sequences have been deposited in GenBank (accession numbers OK382584–OK382941; Data related to this paper may be requested from the authors. However, ivory samples and genetic data derived from them are subject to restricted access (see and for the US regulatory conditions currently governing trade in ivory, which may also apply to availability of samples). Software used in this study is available on GitHub: EBhybrids,; familial matching,; SCAT,; VORONOI,; ivory, analysis, pipeline,


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This works was supported by the Paul and Yaffe Maritz Family Foundation, Wildlife Conservation Network, Elephant Crisis Fund, UN Development Program, the Paul G. Allen Family Foundation, the Woodtiger Fund, the Bureau of International Narcotics and Law Enforcement Affairs of the US Department of State, US Department of Homeland Security, HSI, the World Bank, UN Office on Drugs and Crime, the National Institute of Justice (grant no. 2020-DQ-BX-0022) and National Institutes of Health (grant no. GM075091). The opinions, findings, conclusions and recommendations expressed in this paper are those of the authors and do not necessarily reflect those of the agencies or donors that funded this work. E. Thompson, J. Felsenstein and M. Taper offered statistical advice. M. Winters, R. Booth and E. Reese provided lab assistance. K. Wolfram provided logistical support. Eco Activists for Governance and Law Enforcement (EAGLE), Hong Kong AFCD, HSI-Singapore, HSI-Vietnam, INTERPOL, Kenya Wildlife Service, Mozambique National Administration of Protected Areas, Singapore NPARKS, Uganda Wildlife Authority and Uganda Revenue Authority provided sampling assistance. Environmental Investigation Agency-UK and Maisha Group Ltd contributed physical evidence. The following governments agreed to provide samples from their ivory seizures: Angola, Cote d’Ivoire, Hong Kong, Kenya, Malawi, Malaysia, Mozambique, Philippines, Singapore, Sri Lanka, South Sudan, Taiwan, Thailand, Togo, Uganda, United Arab Emirates and Vietnam.

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Authors and Affiliations



The idea for the study was conceived by S.K.W. Sampling was conducted by S.K.W., J.E.B., A.W., C.J.F. and M.Y.O. Laboratory analyses were conducted by Y.H., Z.A.K., E.J. and K.H. Familial searches and analyses were conducted by C.J.W., M.K.K. and B.S.W. Network analyses were conducted by R.H. and M.K.K. Physical evidence was compiled by J.E.B., C.M. and S.K.W. Manuscript preparation was by S.K.W., M.K.K., C.J.W., J.E.B., C.M. and R.H. Manuscript edits were by S.K.W., C.J.W., J.E.B., C.M., R.H., M.K.K. and B.S.W.

Corresponding author

Correspondence to Samuel K. Wasser.

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The authors declare no competing interests.

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Nature Human Behaviour thanks the anonymous reviewers for their contribution to the peer review of this work. Peer reviewer reports are available.

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Extended data

Extended Data Fig. 1 Genetic matches between tusks found in separate ivory seizures.

Format is the same as in Fig. 3a. Seizure number key: 1 = SGP, 06-02, 6.5t; 2 = HKG, 05-06, 3.9t; 3 = HKG, 07-06, 2.6t; 4 = TWN, 07-06, 1.2t; 5 = TWN, 07-06, 3.0t; 6 = SGP, 03-07, 0.5t; 7 = PHL, 06-09, 4.9t; 8 = VNM, 04-10, 2.2t; 9 = KEN, 08-10, 1.5t; 10 = THA, 01-11, 0.33t; 11 = KEN, 05-11, 1.3t; 12 = MYS, 09-11, 1.1t; 13 = KEN, 12-11, 1.5t; 14 = LKA, 05-12, 1.5t; 15 = UGA, 09-12, Xt,;16 = HKG, 10-12, 1.9tA; 17 = HKG, 10-12, 1.9tB; 18 = MYS, 12-12, 6.0t; 19 = HKG, 01-13, 1.3t; 20 = KEN, 01-13, 3.8t; 21 = ARE, 05-13, 1.5t; 22 = MWI, 05-13, 2.6t; 23 = KEN, 06-13, 1.5t; 24 = HKG, 07-13, 2.0t; 25 = KEN, 07-13, 3.3t; 26 = HKG, 08-13, 2.2t; 27 = TGO, 08-13, 0.7t; 28 = KEN, 10-13, 2.0t; 29 = KEN, 10-13, 2.9t; 30 = UGA, 10-13, 2.9t; 31 = UGA, 12-13, 1.4t; 32 = TGO, 01-14, 3.9t; 33 = SGP, 03-14, 1.0t; 34 = UGA, 05-14, 1.8t; 35 = KEN, 06-14, 2.2t; 36 = UGA, 07-14, 0.6t; 37 = MOZ, 05-15, 1.2t; 38 = SGP, 05-15, 4.6t; 39 = SSD, 06-16, 0.5t; 40 = MYS, 07-16, 0.89t; 41 = KEN, 12-16, 1.0t; 42 = MYS, 01-17, 0.85t; 43 = UGA, 02-17, 1.3t; 44 = HKG, 07-17, 7.2t; 45 = CIV, 01–18, 0.5t; 46 = SGP, 03-18, 3.3t; 47 = AGO, 06-18, 1.8t; 48 = UGA, 01-19, 3.3t; 49 = SGP, 07-19, 8.8t. ISO Key: AGO = Angola, ARE = United Arab Emirates, CIV = Cote d’Ivoire, HKG = Hong Kong, KEN = Kenya, LKA = Sri Lanka, MOZ = Mozambique, MWI = Malawi, MYS = Malaysia, PHL = Philippines, SGP = Singapore, SSD = South Sudan, TGO = Togo, THA = Thailand, TWN = Taiwan, UGA = Uganda, VNM = Vietnam.

Extended Data Fig. 2 Physical-evidence matches between tusks found in separate ivory seizures.

Format is the same as in Fig. 3b.

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Wasser, S.K., Wolock, C.J., Kuhner, M.K. et al. Elephant genotypes reveal the size and connectivity of transnational ivory traffickers. Nat Hum Behav 6, 371–382 (2022).

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