Evaluating welfare of American black bears (Ursus americanus) captured in foot snares and in winter dens

Much research on wild mammals requires trapping, especially livetrapping, yet few methods used to capture wild mammals have been tested against an accepted standard for animal welfare and few data exist regarding physiological responses to capture. My coworkers and I livetrapped 208 American black bears (Ursus americanus) 356 times between May 1981 and August 2001 in the Pisgah National Forest in the Southern Appalachian Mountains by using Aldrich-type foot snares modified for bear safety with automobile hood springs and swivels spliced into cables. We outfitted most bears with transmitter collars and followed 18 bears to their winter dens. We outfitted 8 bears with transponder collars mounted with remotely dischargable darts loaded with anesthesia. We recorded the physical injuries of all bears handled and obtained 186 standard blood chemistry profiles from 112 bears. I compared the blood chemistry profiles of snared bears to profiles of bears in dens, to profiles for healthy, captive bears, and to profiles for wild bears that were collar-darted. Aldrich-type foot snares modified for bear safety, as we used them, and den handling met the accepted standard for trap injuries. Blood chemistry profiles indicated that bears captured in snares experienced high levels of physical exertion and were dehydrated. Blood chemistry parameters responsive to exertion increased with increasing injury scores.