{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T08:40:04Z","timestamp":1768812004909,"version":"3.49.0"},"reference-count":32,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,12]],"date-time":"2021-03-12T00:00:00Z","timestamp":1615507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007463","name":"Rufford Foundation","doi-asserted-by":"publisher","award":["24248-2"],"award-info":[{"award-number":["24248-2"]}],"id":[{"id":"10.13039\/100007463","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Wildlife monitoring is an important part of the conservation strategies for certain endangered species. Non-invasive methods are of significant interest because they preserve the studied animal. The study of signs, especially tracks, seems to be a valuable compromise between reliability, simplicity and feasibility. The main objective of this study is to develop and test an algorithm that can identify individual cheetahs based on 3D track modelling using proximal sensing with an off-the-shelf camera. More specifically, we propose a methodological approach allowing the identification of individuals, their sex and their foot position (i.e., left\/right and hind\/front). In addition, we aim to compare different track recording media: 2D photo and 3D photo models. We sampled 669 tracks from eight semi-captive cheetahs, corresponding to about 20 tracks per foot. We manually placed on each track 25 landmarks: fixed points representing the geometry of an object. We also automatically placed 130 semi-landmarks, landmark allowed to move on the surface, per track on only the 3D models. Geometric morphometrics allowed the measurement of shape variation between tracks, while linear discriminant analysis (LDA) with jack-knife prediction enabled track discrimination using the information from their size and shape. We tested a total of 82 combinations of features in terms of recording medium, landmarks configuration, extracted information and template used. For foot position identification, the best combination correctly identified 98.2% of the tracks. Regarding those results, we also ran an identification algorithm on a dataset containing only one kind of foot position to highlight the differences and mimic an algorithm identifying the foot position first and then an individual factor (here, sex and identity). This led to accuracy of 94.8 and 93.7%, respectively, for sex and individual identification. These tools appear to be effective in discriminating foot position, sex and individual identity from tracks. Future works should focus on automating track segmentation and landmark positioning for ease of use in conservation strategies.<\/jats:p>","DOI":"10.3390\/rs13061090","type":"journal-article","created":{"date-parts":[[2021,3,14]],"date-time":"2021-03-14T23:52:06Z","timestamp":1615765926000},"page":"1090","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Individual Identification of Cheetah (Acinonyx jubatus) Based on Close-Range Remote Sensing: First Steps of a New Monitoring Technique"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2700-586X","authenticated-orcid":false,"given":"Guillaume","family":"Baralle","sequence":"first","affiliation":[{"name":"Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre (Forest is Life), University of Li\u00e8ge, 2 Passage des D\u00e9port\u00e9s, 5030 Gembloux, Belgium"}]},{"given":"Antoine F. J.","family":"Marchal","sequence":"additional","affiliation":[{"name":"Wildlife 3D Tracking (W3DT), rue des Ponts 98, 1480 Tubize, Belgium"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9987-9673","authenticated-orcid":false,"given":"Philippe","family":"Lejeune","sequence":"additional","affiliation":[{"name":"Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre (Forest is Life), University of Li\u00e8ge, 2 Passage des D\u00e9port\u00e9s, 5030 Gembloux, Belgium"},{"name":"Wildlife 3D Tracking (W3DT), rue des Ponts 98, 1480 Tubize, Belgium"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4329-6422","authenticated-orcid":false,"given":"Adrien","family":"Michez","sequence":"additional","affiliation":[{"name":"Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre (Forest is Life), University of Li\u00e8ge, 2 Passage des D\u00e9port\u00e9s, 5030 Gembloux, Belgium"},{"name":"University Rennes 2 LETG (CNRS UMR 6554), Place du Recteur Henri Le Moal, CEDEX, 35043 Rennes, France"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"494","DOI":"10.1126\/science.277.5325.494","article-title":"Human Domination of Earth","volume":"227","author":"Vitousek","year":"1997","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"E6089","DOI":"10.1073\/pnas.1704949114","article-title":"Biological Annihilation via the Ongoing Sixth Mass Extinction Signaled by Vertebrate Population Losses and Declines","volume":"114","author":"Ceballos","year":"2017","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Cardillo, M., Purvis, A., Sechrest, W., Gittleman, J.L., Bielby, J., and Mace, G.M. (2004). Human Population Density and Extinction Risk in the World\u2019s Carnivores. PLoS Biol., 2.","DOI":"10.1371\/journal.pbio.0020197"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1017\/S003060530843106X","article-title":"Carnivore Conservation at the Crossroads","volume":"43","author":"Karanth","year":"2009","journal-title":"ORYX"},{"key":"ref_5","unstructured":"Durant, S., Mitchell, N., Ipavec, A., and Groom, R. (2015). Acinonyx Jubatus (Cheetah). IUCN Red List."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1073\/pnas.1611122114","article-title":"The Global Decline of Cheetah Acinonyx Jubatus and What It Means for Conservation","volume":"114","author":"Durant","year":"2017","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Marker, L., Cristescu, B., Dickman, A., Nghikembua, M.T., Boast, L.K., Morrison, T., Melzheimer, J., Fabiano, E., Mills, G., and Wachter, B. (2017). Ecology of Free-Ranging Cheetahs. Cheetahs: Biology and Conservation, Academic Press. Biodiversity of the World: Conservation from Genes to Landscapes.","DOI":"10.1016\/B978-0-12-804088-1.00008-3"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"West, G., Heard, D., and Caulkett, N. (2014). Zoo Animal and Wildlife Immobilization and Anesthesia, John Wiley and Sons. [2nd ed.].","DOI":"10.1002\/9781118792919"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1017\/S0030605306001414","article-title":"Remote Camera-Trap Methods and Analyses Reveal Impacts of Rangeland Management on Namibian Carnivore Communities","volume":"41","author":"Kauffman","year":"2007","journal-title":"Oryx"},{"key":"ref_10","unstructured":"Liebenberg, L. (1990). A Field Guide to Animal Tracks of Southern Africa, David Philip Publishers."},{"key":"ref_11","unstructured":"Liebenberg, L. (1990). The Art of Tracking, the Origin of Science, David Philip Publishers."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1111\/j.1469-7998.1997.tb05805.x","article-title":"Tracking and the Interpretation of Spoor: A Scientifically Sound Method in Ecology","volume":"242","author":"Stander","year":"1997","journal-title":"J. Zool."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/0006-3207(93)90196-8","article-title":"A Rigorous Technique for Identifying Individual Mountain Lions Felis Concolor by Their Tracks","volume":"65","author":"Smallwood","year":"1993","journal-title":"Biol. Conserv."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"205","DOI":"10.3354\/esr00067","article-title":"A Footprint Technique to Identify White Rhino Ceratotherium Simum at Individual and Species Levels","volume":"4","author":"Alibhai","year":"2008","journal-title":"Endanger. Species Res."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Alibhai, S., Jewell, Z., and Evans, J. (2017). The Challenge of Monitoring Elusive Large Carnivores: An Accurate and Cost-Effective Tool to Identify and Sex Pumas (Puma Concolor) from Footprints. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0172065"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Jewell, Z., and Alibhai, S. (2012). Identifying Endangered Species from Footprints. SPIE.","DOI":"10.1117\/2.1201212.004636"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Jewell, Z.C., Alibhai, S.K., Weise, F., Munro, S., Van Vuuren, M., and Van Vuuren, R. (2016). Spotting Cheetahs: Identifying Individuals by Their Footprints. J. Vis. Exp., 2016.","DOI":"10.3791\/54034"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1111\/jzo.12342","article-title":"Virtual Plaster Cast: Digital 3D Modelling of Lion Paws and Tracks Using Close-Range Photogrammetry","volume":"300","author":"Marchal","year":"2016","journal-title":"J. Zool."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"106","DOI":"10.3957\/056.047.0106","article-title":"de Identification of the Anteroposterior and Mediolateral Position of Lion Paws and Tracks Using 3D Geometric Morphometrics","volume":"47","author":"Marchal","year":"2017","journal-title":"Afr. J. Wildl. Res."},{"key":"ref_20","unstructured":"Marchal, A.F.J. (2017). Monitoring Lions (Panthera Leo) Using Digital 3D Models of Their Tracks. [Ph.D. Thesis, Universit\u00e9 de Li\u00e8ge]."},{"key":"ref_21","unstructured":"Zelditch, M.L., Swiderski, D.L., Sheets, H.D., and Fink, W.L. (2004). Geometric Morphometrics for Biologists: A Primer, Academic Press."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1007\/s11692-009-9055-x","article-title":"Advances in Geometric Morphometrics","volume":"36","author":"Mitteroecker","year":"2009","journal-title":"Evol. Biol."},{"key":"ref_23","unstructured":"Gunz, P., and Mitteroecker, P. (2013). Semilandmarks: A Method for Quantifying Curves and Surfaces. Hystrix, 24."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Bookstein, F.L. (1991). Morphometric Tools for Landmark Data: Geometry and Biology, Cambridge University Press.","DOI":"10.1017\/CBO9780511573064"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Cucchi, T., Baylac, M., Evin, A., Bignon-Lau, O., and Vigne, J.-D. (2015). Morphom\u00e9trie g\u00e9om\u00e9trique et arch\u00e9ozoologie: Concepts, m\u00e9thodes et applications. Messages d\u2019os Arch\u00e9om\u00e9trie du Squelette, Editions des Archives Contemporaines.","DOI":"10.17184\/eac.3997"},{"key":"ref_26","unstructured":"Sherratt, E. (2021, March 01). Quick Guide to Geomorph v.2.1.6, Available online: https:\/\/www.researchgate.net\/profile\/Ariel_Marcy\/post\/Morphometry_and_convergence_divergence\/attachment\/59d63b0879197b8077998163\/AS%3A408679657558016%401474448231372\/download\/Quick_Guide_to_Geomorph_v2.1.pdf."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"840","DOI":"10.1644\/BRB-036","article-title":"Morphology, Physical Condition, and Growth of the Cheetah (Acinonyx Jubatus Jubatus)","volume":"84","author":"Marker","year":"2003","journal-title":"J. Mammal."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Schanz, T., Lins, Y., Viefhaus, H., Barciaga, T., L\u00e4be, S., Preuschoft, H., Witzel, U., Sander, P.M., and Dodson, P. (2013). Quantitative Interpretation of Tracks for Determination of Body Mass. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0077606"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1192","DOI":"10.2307\/3808191","article-title":"Age Estimation and Population Age Structure of Elephants from Footprint Dimensions","volume":"47","author":"Western","year":"1983","journal-title":"J. Wildl. Manag."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1111\/j.1469-7998.1983.tb05100.x","article-title":"Postnatal Development of Gait Behaviour and Functional Allometry in the Domestic Cat (Felis Catus)","volume":"199","author":"Peters","year":"1983","journal-title":"J. Zool."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1002\/wsb.432","article-title":"Sex Determination of Amur Tigers (Panthera Tigris Altaica) from Footprints in Snow","volume":"38","author":"Gu","year":"2014","journal-title":"Wildl. Soc. Bull."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2007","DOI":"10.1890\/08-1069.1","article-title":"Automatic Track Recognition of Footprints for Identifying Cryptic Species","volume":"90","author":"Russell","year":"2009","journal-title":"Ecology"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/6\/1090\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:35:00Z","timestamp":1760160900000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/6\/1090"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,12]]},"references-count":32,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["rs13061090"],"URL":"https:\/\/doi.org\/10.3390\/rs13061090","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,12]]}}}