This study refines a method developed by Smallwood and Fitzhugh (1993), which attempted to discriminate between individual mountain lions (Puma concolor) in the field by using measurements of their tracks. During January-March 1996, we followed 10 radio collared mountain lions in the Sierra Nevada mountains of California and obtained photographs of their tracks in the soil and mow. In addition, track measurements were obtained from 4 mountain lion carcasses from different parts of California in 1996-1997. We analyzed heel pad variability to discriminate between mountain lions. Measurements of each track were taken every 10 degrees from the center of the heel pad until the entire heel pad was characterized by a series of linear measurements, corresponding to a particular angle measurement. After measurements of each heel pad were made, a curve was produced by cubic spline modeling which was indicative of a particular heel pad for each mountain lion. Confidence bands were placed around each curve and a graphical comparison was then made between track sets. The results of this analysis indicate that for both types of track sets, it is difficult to distinguish between mountain lions based on levels of heel pad variability. We conclude that measurements associated entirely with mountain lion heel pad lack discriminatory power and make recommendations abut what types of measurements could be used to efficiently and accurately assess an animal's identity.
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