Carbon dating rhino horn
We analysed all rhino horn items offered for sale in through UK auction houses, to answer the following questions: The twelve-month survey followed auction house room sales for which online bidding was also possible via one or more of three sales platforms. It also included sales by one major auction house that sold a significant number of high-value items through its own online bidding system. The survey did not include items sold by antique dealers, antique shops or private sales, nor sales on the wider internet. We documented how they were advertised, which auction houses they were sold at, and the sale outcome.
We did not purchase any items for testing, nor intervene in any of the sales. Please see here for the full report with further details. Areas of further research have been identified. Lag time increases from onward, ranging from 13 to 32 mo Fig. This trend of increasing lag time is most evident in East African seizures where there are a total of nine seizures made over 9 y. The reason for the general increase in lag time since is unclear.
It is likely related to the overall decline in African elephant populations, particularly from to , where data show population decline due to unsustainable poaching rates, especially in Central and East Africa 3 , 4. As a result, it may take longer to accumulate enough large tusks to make a large shipment more profitable. Considering the markedly slower growth rate of tusks of forest elephants, this may also explain the longer lag times we observed for Central African ivory compared with East African ivory. West African forest ivory generally made up a small portion of the tusks in all seizures analyzed and, based on its short lag time, seemed to be added opportunistically at the time of shipment.
Factors related to the dynamics of the illegal network of trade or perhaps to changes in the demand for ivory 29 , 30 may have also contributed to these trends. Median lag time months plotted versus seizure date from to There seems to be an increase in lag time beginning in A calibration curve for F 14 C of modern wildlife tissues in Africa shows that modern elephant hair samples keratin have an offset with respect to the bomb curve between about 1 and 2 y from both the NH zone 3 NH3 and SH zone 3 SH3 relationships, with the tissue samples having higher F 14 C values than either the NH3 or SH3 curves.
This is likely due to elephant diets that include carbon that was fixed some months to years before ingestion, and also due to recycling of some proteins during keratin or collagen synthesis. The elephant hair calibration curve can be used to determine the date of death of elephants if the F 14 C of ivory is measured along the pulp cavity of the tusk. It may be necessary to establish taxon-specific calibration curves for date-of-death determinations based on radiocarbon dating of other wildlife products, such as rhinoceros horn, pangolin scales, pelts or furs, or timber.
Issues specific to different dietary i. Examination of ivory samples from 14 seizures made between and shows that the lag time between elephant death and seizure by law enforcement officials has median values generally ranging between 6 and 35 mo. Specimens originating from East Africa—previously determined via genetic analysis—have the shortest lag times, with ca. We find no evidence that long-term government or other stockpiles have been contributing significant amounts of ivory to the illegal ivory trade, emphasizing that poached ivory is being rapidly moved into the illegal trade.
This study demonstrates the power of bomb-curve radiocarbon dating for revealing lag times between date of death and seizure, a technique that can be applied to seizures of other wildlife parts, providing critical information to law enforcement, conservation, government, and policy organizations and agencies. We report elephant hair and ivory 14 C measurements in this paper.
We sampled the innermost dentine in the pulp cavity for samples used to assign date of death to animals Fig. S2 ; for selected specimens, we also dated the outermost dentine, which often had an outer sheath of cementum that was sampled. Powder was obtained using a high-speed rotary Dremel tool and double-cut carbide bits from the innermost 1—2 mm of the ivory block. Hair samples were obtained during collaring or translocation operations conducted by Save the Elephants and by the Kenya Wildlife Service.
The basal 1 cm of hair was analyzed for DNA markers; the subsequent 2 mm i. Dates were corrected to ca. CO 2 was cryogenically purified and reduced to graphite; graphite from each sample was thereafter pressed into a target for radiocarbon 14 C measurement. The graphite targets were sent to the W. Expanded uncertainty in lag time incorporates uncertainty in the calibration curve Fig. U is calculated from a linear combination of this measurement uncertainty and predicted values from the elephant hair calibration curve, multiplied by a coverage factor k of 2, which represents ca.
For seized specimens with measured F 14 C values similar to those of the elephant hair used to build the calibration curve e. One seized ivory specimen had an F 14 C value of 1. Normal distributions to histograms of lag times Fig. We thank Tara Wilson for help processing the seizures for analysis, Mark Franklin for help with sampling of ivory specimens for radiocarbon dating, and John Howa and Michael Lott for help with expanded uncertainty calculations.
This work was funded by Paul G. The following governments agreed to provide samples from their ivory seizures: Conflict of interest statement: This article contains supporting information online at www. National Center for Biotechnology Information , U. Published online Nov 7. Cerling , a, b, c, 1 Janet E.
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Barnette , a Lesley A. Gobush , f Kevin T. Uno , g Samuel K. Wasser , h and Xiaomei Xu i. Cerling a IsoForensics, Inc. Barnette a IsoForensics, Inc. Chesson a IsoForensics, Inc. Gobush f Wildlife Program, Vulcan, Inc. Author information Copyright and License information Disclaimer. Contributed by Thure E. This article has been cited by other articles in PMC. Significance C dating methods can be used to determine the time of death of wildlife products.
Open in a separate window. Carbon data for calibration curve from elephant hair collected on known dates. Radial Growth Rates of Tusks. Radial tusk growth rates calculated from multiple carbon analyses of ivory.
Carbon dating rhino horn. Carbon dating rhino horn - ycigigegic.tk
Date-of-Death Determinations of Seized Ivory. East Africa, Tridom, and West Africa.
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Results from these different assignments are listed separately. Very Old Ivory in Seizures. Changes in Lag Times from to Conclusions A calibration curve for F 14 C of modern wildlife tissues in Africa shows that modern elephant hair samples keratin have an offset with respect to the bomb curve between about 1 and 2 y from both the NH zone 3 NH3 and SH zone 3 SH3 relationships, with the tissue samples having higher F 14 C values than either the NH3 or SH3 curves. Methods We report elephant hair and ivory 14 C measurements in this paper.
Supplementary Material Supplementary File Click here to view. Acknowledgments We thank Tara Wilson for help processing the seizures for analysis, Mark Franklin for help with sampling of ivory specimens for radiocarbon dating, and John Howa and Michael Lott for help with expanded uncertainty calculations. Footnotes Conflict of interest statement: United Nations Office of Drugs and Crime. Guidelines for methods and procedures of ivory sampling and laboratory analysis.
Wasser SK, et al. Wittemyer G, et al. Illegal killing for ivory drives global decline in African elephants. Chase MJ, et al. Continent-wide survey reveals massive decline in African savannah elephants. Maisels F, et al. Devastating decline of forest elephants in central Africa. Slow intrinsic growth rate in forest elephants indicates recovery from poaching will require decades.
Carbon Test Determines Whether A Piece Of Ivory Is Legal Or Illegal
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