title: Capture, anesthesia, and disturbance of free-ranging brown bears (Ursus arctos) during hibernation.
abstract: We conducted thirteen immobilizations of previously collared hibernating two- to four-year-old brown bears (Ursus arctos) weighing 21-66 kg in central Sweden in winter 2010 and 2011 for comparative physiology research. Here we report, for the first time, an effective protocol for the capture and anesthesia of free-ranging brown bears during hibernation and an assessment of the disturbance the captures caused. Bears were darted in anthill, soil, or uprooted tree dens on eleven occasions, but two bears in rock dens fled and were darted outside the den. We used medetomidine at 0.02-0.06 mg/kg and zolazepam-tiletamine at 0.9-2.8 mg/kg for anesthesia. In addition, ketamine at 1.5 mg/kg was hand-injected intramuscularly in four bears and in six it was included in the dart at 1.1-3.0 mg/kg. Once anesthetized, bears were removed from the dens. In nine bears, arterial blood samples were analyzed immediately with a portable blood gas analyzer. We corrected hypoxemia in seven bears (PaO(2) 57-74 mmHg) with supplemental oxygen. We placed the bears back into the dens and antagonized the effect of medetomidine with atipamezole. Capturing bears in the den significantly increased the risk of den abandonment. One of twelve collared bears that were captured remained at the original den until spring, and eleven, left their dens (mean ± standard deviation) 3.2±3.6 (range 0.5-10.5) days after capture. They used 1.9±0.9 intermediate resting sites, during 6.2±7.8 days before entering a new permanent den. The eleven new permanent dens were located 730±589 m from the original dens. We documented that it was feasible and safe to capture hibernating brown bears, although they behaved differently than black bears. When doing so, researchers should use 25% of the doses used for helicopter darting during the active period and should consider increased energetic costs associated with den abandonment.
authors: Department of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad, Elverum, Norway. alina.evans@hihm.com
authors: Alina L
authors: AL
authors: Evans
authors: Veronica
authors: V
authors: Sahlén
authors: Ole-Gunnar
authors: OG
authors: Støen
authors: Åsa
authors: Å
authors: Fahlman
authors: Sven
authors: S
authors: Brunberg
authors: Knut
authors: K
authors: Madslien
authors: Ole
authors: O
authors: Fröbert
authors: Jon E
authors: JE
authors: Swenson
authors: Jon M
authors: JM
authors: Arnemo
mesh_terms: D000758:Anesthesia / Q000009:adverse effects* / Q000379:methods*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D004338:Drug Combinations; D005260:Female; D006605:Hibernation; D008297:Male; D020926:Medetomidine / Q000009:adverse effects / Q000494:pharmacology; D009068:Movement / Q000187:drug effects*; D010100:Oxygen / Q000378:metabolism; D012621:Seasons; D013992:Tiletamine / Q000009:adverse effects / Q000494:pharmacology; D001503:Ursidae / Q000378:metabolism / Q000502:physiology*; D015041:Zolazepam / Q000009:adverse effects / Q000494:pharmacology
chemical_list: D004338:Drug Combinations; C006131:tiletamine, zolazepam drug combination; D013992:Tiletamine; D015041:Zolazepam; D020926:Medetomidine; D010100:Oxygen