Individual Identification of Raccoons (Procyon lotor) Using Track Plate Foot Printing

Abstract

Population studies are widely used in conservation and management efforts, but acquiring necessary data sets can be difficult. Convenience sampling or camera monitoring may result in biased outcomes, while explicit approaches such as genetic analysis may be impractical due to cost and time. Traditional mark recapture methods are frequently intrusive and pose risk to both animals and handlers that could lead to mortality. These factors highlight the need for a simple, inexpensive, and non-invasive approach to assess species density. One possible technique which addresses these issues is track plate footprinting. We collected raccoon (Procyon lotor) footprints and examined the ability to distinguish individuals by their metacarpal pads from a 225 ha reserve. The probability of identity (PID) for back right feet ranged from 5.72 × 10−9 – 6.71 × 10−12 and from 3.34 × 10−8 – 3.55 × 10−10 for the back left feet, indicating that it was unlikely any two raccoons shared the same papillae pattern. The minimum number of raccoons known to be alive was estimated to be 12–17 individuals depending upon the foot and scale of resolution used, with estimates from program the Capture ranging from 34–38 raccoons. Our results show that track plate footprint can be used to unambiguously identify individual raccoons, may be useful in mark-recapture studies, and is likely to be applicable to other species with large pads.