Stress Response of Stone Martens and Red Foxes in Two Different Live Traps

Trapping of terrestrial animals is an important tool for harvest, pest control and research worldwide. To catch animals alive, animal welfare has to be ensured, which is reflected in different agreements on trading and trapping of animals between sovereign nations (Council Regulation [EEC] No 3254/91). The red fox (Vulpes vulpes) and stone marten (Martes foina) represent important predatory animals. Their influence on protected species as well as their increasing appearance in urban areas demand responsible handling. In our study, we evaluated 2 trap systems used for trapping red foxes and stone martens in accordance with criteria stipulated in the Agreement on International Humane Trapping Standards (AIHTS) and International Organisation for Standardisation 10990 Part 5 – Methods for Testing Restraining Traps (ISO 10990). In total, we captured 20 red foxes in a concrete pipe vault trap and 13 stone martens in a Strack’s wooden box trap in Schleswig-Holstein, Germany, and observed their behavior inside each trap. After anesthesia, a clinical examination of each animal was conducted, and blood and hair samples were taken. After euthanasia, radiological examinations of the full body were taken, and necropsies and histopathological investigations were performed. No trap-associated lesions were found. Hormone analysis showed no remarkable signs of stress for the animals, according to state-of-the-art methods. Apart from serum cortisol, the quotient of dehydroepiandrosterone in serum and hair seems to be the most predictive value on stress response of the 2 different species. Video observation of the trapped animals emerged as a valuable tool to estimate animal welfare by behavior. This study complements AIHTS and ISO 10990 criteria with results on behavior and hormone analysis, being an additional benefit when evaluating animal welfare of each trapping system.