Evaluating the Factors that Impact Wild Pig Performance as Judas Pigs

Abstract

The Judas technique, as applied to wild pigs (Sus scrofa), is an approach in which a wild pig is marked, released, and then used to locate other wild pigs for subsequent removal(s). Previous Judas pig studies are inconclusive regarding effectiveness of the technique and whether sex of the Judas pig influences efficacy. We evaluated efficacy of Judas pigs within a whole sounder removal effort, in which sounders were trapped, a Judas pig was tagged and released, and the remaining wild pigs were humanely dispatched. We monitored 14 wild pigs for 2 to 15 months in Calhoun County, Georgia between March 2021 and July 2023. We used camera trapping to record the presence of other wild pigs with the Judas pig and measured time to initial encounter with other wild pigs, average group size associated with the Judas pig, percentage of Judas pig photos with other wild pigs, and number of unique wild pigs associated with Judas pigs. Sex of Judas pig had no relationship with three of four evaluation metrics. On average, Judas pigs took 35 days to locate other wild pigs, were detected with an average of 2.20 wild pigs, and were detected with other wild pigs in 59.5% of photographs taken after first detection with other wild pigs. Judas pigs associated with an average of 9.79 unique wild pigs, with female Judas pigs observed with more unique individuals than male Judas pigs, supporting the assumption that female wild pigs are more social. There was a 78.6% chance the Judas pigs were with other wild pigs after 40 days of deployment, and all Judas pigs located other wild pigs in ≤ 85 days. These findings further support using Judas pigs as a method to locate other wild pigs for removal.