Use of handheld X-ray fluorescence as a non-invasive method to distinguish between Asian and African elephant tusks.
We describe the use of handheld X-ray fluorescence, for elephant tusk species identification. Asian (n = 72) and African (n = 85) elephant tusks were scanned and we utilized the species differences in elemental composition to develop a functional model differentiating between species with high precision. Spatially, the majority of measured elements (n = 26) exhibited a homogeneous distribution in cross-section, but a more heterologous pattern in the longitudinal direction. Twenty-one of twenty four elements differed between Asian and African samples. Data were subjected to hierarchical cluster analysis followed by a stepwise discriminant analysis, which identified elements for the functional equation. The best equation consisted of ratios of Si, S, Cl, Ti, Mn, Ag, Sb and W, with Zr as the denominator. Next, Bayesian binary regression model analysis was conducted to predict the probability that a tusk would be of African origin. A cut-off value was established to improve discrimination. This Bayesian hybrid classification model was then validated by scanning an additional 30 Asian and 41 African tusks, which showed high accuracy (94%) and precision (95%) rates. We conclude that handheld XRF is an accurate, non-invasive method to discriminate origin of elephant tusks provides rapid results applicable to use in the field.
Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Kittisak
K
Buddhachat
Center of Excellence in Elephant Research and Education, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.|Maesa Elephant camp, 119/9, Tapae Road, Muang, Chiang Mai 50100, Thailand.
Chatchote
C
Thitaram
Smithsonian Conservation Biology Institute, Center for Species Survival, 1500 Remount Road, Front Royal, VA 22630, USA.
Janine L
JL
Brown
Center of Excellence in Elephant Research and Education, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Sarisa
S
Klinhom
Center of Excellence in Elephant Research and Education, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Pakkanut
P
Bansiddhi
DNP Wildlife Forensic Science Unit (DNP-WIFOS), Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation. 61 Phaholyothin Rd., Chatuchak Bangkok 10900 Thailand.
Kitichaya
K
Penchart
DNP Wildlife Forensic Science Unit (DNP-WIFOS), Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation. 61 Phaholyothin Rd., Chatuchak Bangkok 10900 Thailand.
Kanita
K
Ouitavon
DNP Wildlife Forensic Science Unit (DNP-WIFOS), Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation. 61 Phaholyothin Rd., Chatuchak Bangkok 10900 Thailand.
Khanittha
K
Sriaksorn
Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation. 61 Phaholyothin Rd., Chatuchak Bangkok 10900 Thailand.
Chalermpol
C
Pa-in
Wildlife Research Division, Wildlife Conservation Office, Department of National Parks, Wildlife and Plant Conservation. 61 Phaholyothin Rd., Chatuchak Bangkok 10900 Thailand.
Budsabong
B
Kanchanasaka
Center of Excellence in Elephant Research and Education, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Chaleamchat
C
Somgird
Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.|Center of Excellence in Elephant Research and Education, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Korakot
K
Nganvongpanit
D000349:Africa; D000818:Animals; D001208:Asia; D004606:Elephants; D005260:Female; D005453:Fluorescence; D005470:Fluorometry; D008297:Male; D014965:X-Rays