A Multi-Point Identification Approach for the Recognition of Individual Leopards (Panthera pardus kotiya)

Abstract

Visual leopard identifications performed with camera traps using the capture–recapture method only consider areas of the skin that are visible to the equipment. The method presented here considered the spot or rosette formations of either the two flanks or the face, and the captured images were then compared and matched with available photographs. Leopards were classified as new individuals if no matches were found in the existing set of photos. It was previously assumed that an individual leopard’s spot or rosette pattern would not change. We established that the spot and rosette patterns change over time and that these changes are the result of injuries in certain cases. When compared to the original patterns, the number of spots may be lost or reduced, and some spots or patterns may change in terms of their prominence, shape, and size. We called these changes “obliterate changes” and “rejig changes”, respectively. The implementation of an earlier method resulted in a duplication of leopard counts, achieving an error rate of more than 15% in the population at Yala National Park. The same leopard could be misidentified and counted multiple times, causing overestimated populations. To address this issue, we created a new two-step methodology for identifying Sri Lankan leopards. The multi-point identification method requires the evaluation of at least 9–10 spot areas before a leopard can be identified. Moreover, the minimum leopard population at the YNP 1 comprises at least 77 leopards and has a density of 0.5461 leopards per km2.

A unique single nucleotide polymorphism in Agouti Signalling Protein (ASIP) gene changes coat colour of Sri Lankan leopard (Panthera pardus kotiya) to dark black

“…From visual data, the Sri Lankan Leopard’s spot and rosette pattern was distinct from the other leopards [ 87 ]. The shapes, sizes, and formations of spot and rosette formations are unique to every leopard [ 35 , 88 ].…”

A unique single nucleotide polymorphism in Agouti Signalling Protein (ASIP) gene changes coat colour of Sri Lankan Leopard (Panthera pardus kotiya) to dark black

“…From visual data, Sri Lankan Leopard's Spot and Rosette pattern was distinct from the other leopards (42). The shapes, sizes, and formations of spot and rosette formations are unique to every leopard (29,43).…”

“…Reconstruction of the phylogenetic history of the leopards provides information on species, subspecies, and population genetic status, essential for the conservation of these threatened animals (12). The unique features of the leopards, for example, rosette pattern, spot size, and coat assist in resolving phylogeography relationships between the leopards (13)(14)(15). Molecular data have strengthened the conservation studies on other cat species; snow leopards, lions, and tigers (16,17).…”

Individual identification and photographic techniques in mammalian ecological and behavioural research—Part 2: Field studies and applications

“…We hope that our observations of these patterns will be useful for researchers planning future studies. Although our sample size is limited by the number of submitted manuscripts, it is apparent that the concept of equal catchability (e.g., Jolly and Dickson 1983;Hammond 1990;McKnight and Ligon 2017), the implications of mark change (e.g., Carlson and Mayo 1990;Yoshizaki et al 2009;Wattegedera et al 2022), and the interplay between image quality and individual distinctiveness (e.g., Friday et al 2000Friday et al , 2008Urian et al 2015;Elliser et al 2022) are not yet understood and applied as commonly as one would have expected. Interestingly, these deficiencies were considerably more frequent in studies of terrestrial than marine mammals, contributing to a higher rejection rate of terrestrial studies submitted to this Special Issue.…”