The Leading Edge of Brown Bear
Capture-Anesthesia Methodology
Key Points
The current anesthetic drug combination for free-ranging brown bears has been used since 1992.
The anesthetic protocol (SOP) has been refined and improved based on numerous scientific studies. A new version is now available.
Anesthesia, analgesia, monitoring, supportive care, and surgery follow best practice guidelines established in veterinary medicine.
From 1992 through 2023, 2,325 helicopter-based captures were carried out between April and June on 906 individuals. The mortality rate during capture and the following 3 days was 0.7% (n=15).
From 2010 through 2023, 79 captures of 59 hibernating subadult bears were captured in their dens between February and March using a modified anesthetic protocol. There was no mortality.
Development of the SBBRP anesthetic protocol
Initially, anesthetic monitoring was very limited and only vital signs (pulse rate, respiratory rate, and rectal temperature) were assessed and recorded. In the 1990s, a portable pulse oximeter was introduced for routine monitoring of blood oxygenation. After 2000, however, the SBBRP anesthetic protocol was significantly improved based on numerous scientific studies carried out as part of the project. This includes more frequent recording of vital signs, supplemental oxygen delivery in all bears, administration (if needed) of intravenous fluids and analgesics and best-practice guidelines for invasive sampling and surgical procedures. For example, in 2006 we began providing supplemental oxygen to anesthetized bears which reduced their chances of hypoxemia (low oxygen concentration in the blood) during capture (1-3).
We have since continually evaluated the effect of our capture methodologies, assessing bears physiological responses to anesthesia and capture protocols, and providing recommendations for future monitoring and methodologies within our project and to other brown bear capture and monitoring projects around the world (4-13). For example, we have provided in-depth guidelines on brown bear capture best-practices. This includes recommendations to use “experienced professional capture teams, 2) developing and following a capture protocol specific to each species, and 3) requiring that a mortality assessment be undertaken after any capture-related death” (14). A new and extensive biomedical protocol for Scandinavian brown bears is now available (15)
References
1. Evans AL, Sahlén V, Støen O-G, Fahlman Å, Brunberg S, Madslien K, et al. Capture, anesthesia, and disturbance of free-ranging brown bears (Ursus arctos) during hibernation. PloS one. 2012;7(7):e40520.
2. Fahlman Å, Caulkett N, Arnemo JM, Neuhaus P, Ruckstuhl KE. Efficacy of a portable oxygen concentrator with pulsed delivery for treatment of hypoxemia during anesthesia of wildlife. Journal of Zoo and Wildlife Medicine. 2012;43(1):67-76.
3. Fahlman Å, Pringle J, Arnemo JM, Swenson JE, Brunberg S, Nyman G. Treatment of hypoxemia during anesthesia of brown bears (Ursus arctos). Journal of Zoo and Wildlife Medicine. 2010;41(1):161-4.
4. Fahlman Å, Arnemo JM, Swenson JE, Pringle J, Brunberg S, Nyman G. Physiologic evaluation of capture and anesthesia with medetomidine–zolazepam–tiletamine in brown bears (Ursus arctos). Journal of Zoo and Wildlife Medicine. 2011;42(1):1-11.
5. Fandos Esteruelas N, Cattet M, Zedrosser A, Stenhouse GB, Küker S, Evans AL, et al. A double-blinded, randomized comparison of medetomidine-tiletamine-zolazepam and dexmedetomidine-tiletamine-zolazepam anesthesia in free-ranging brown bears (Ursus arctos). PloS one. 2017;12(1):e0170764.
6. Fandos Esteruelas N, Huber N, Evans AL, Zedrosser A, Cattet M, Palomares F, et al. Leukocyte coping capacity as a tool to assess capture-and handling-induced stress in scandinavian brown bears (Ursus arctos). J Wildlife Dis. 2016;52(2s):S40-S53.
7. Painer J, Zedrosser A, Arnemo JM, Fahlman Å, Brunberg S, Segerström P, et al. Effects of different doses of medetomidine and tiletamine–zolazepam on the duration of induction and immobilization in free-ranging yearling brown bears (Ursus arctos). Canadian journal of zoology. 2012;90(6):753-7.
8. Ozeki LM, Caulkett N, Stenhouse G, Arnemo JM, Fahlman Å. Effect of active cooling and α-2 adrenoceptor antagonism on core temperature in anesthetized brown bears (Ursus arctos). Journal of zoo and wildlife medicine. 2015;46(2):279-85.
9. Ozeki LM, Fahlman Å, Stenhouse G, Arnemo JM, Caulkett N. Evaluation of the accuracy of different methods of monitoring body temperature in anesthetized brown bears (Ursus arctos). Journal of Zoo and Wildlife Medicine. 2014:819-24.
10. Morelli J, Briganti A, Fuchs B, Huber Ð, Evans AL, Reljić S, et al. Comparison of two non-invasive arterial blood pressure monitoring techniques in brown bears (Ursus arctos). Veterinary and Animal Science. 2020;9:100094.
11. Jørgensen PG, Arnemo J, Swenson JE, Jensen JS, Galatius S, Frøbert O. Low cardiac output as physiological phenomenon in hibernating, free-ranging Scandinavian brown bears (Ursus arctos) – An observational study. Cardiovascular Ultrasound. 2014;12:1-6.
12. Jørgensen PG, Evans A, Kindberg J, Olsen LH, Galatius S, Fröbert O. Cardiac adaptation in hibernating, free-ranging Scandinavian Brown Bears (Ursus arctos). Sci Rep-Uk. 2020;10(1):247.
13. Gandolf AR, Fahlman Å, Arnemo JM, Dooley JL, Hamlin R. Baseline normal values and phylogenetic class of the electrocardiogram of anesthetized free-ranging brown bears (Ursus arctos). J Wildlife Dis. 2010;46(3):724-30.
14. Arnemo JM, Ahlqvist P, Andersen R, Berntsen F, Ericsson G, Odden J, et al. Risk of capture‐related mortality in large free‐ranging mammals: Experiences from Scandinavia. Wildlife Biology. 2006;12(1):109-13.
15. Græsli A, Arnemo J, Evans A. Biomedical protocol. Brown bears (Ursus arctos). Evenstad: Inland University of Applied Sciences; 2024.