Winter blood values of selected parameters in a group of non-hibernating captive brown bears (Ursus arctos)

Abstract

Bears undergo some significant changes reflected in blood values during winter season. The most significant are reduced urea and increased creatinine, by some authors considered to be physiological indicators of hibernation. Studied group of six captive brown bears (Ursus arctos) showed decreased activity in winter but were accepting food and walked outdoors. Blood parameters assessed in February 2011 revealed mean values of leucocytes and neutrophils as significantly lower, and creatinine significantly increased compared to captive and free living bears sampled during other seasons when bears are active.

Hibernating or not hibernating? Brown bears’ response to a mismatch between environmental natural cues and captive management, and its welfare implications

“…Studies on bears whose management was not focused on hibernation (i.e., bears kept yearly on a regular feeding schedule) reported only a slight seasonal variability in behavior [ 31 , 50 ], physiology [ 30 , 50 ], and body mass (mentioned in [ 30 ] [Unpublished]), labelling bears as non-hibernating. Despite this, similarities with the wild hibernating conspecifics were mentioned at the physiological level, namely for insulin resistance (American black bears [ 30 ]), and creatinine, both increasing during winter season [ 50 ]. Insulin resistance, in particular, characterizes an independent seasonal change in metabolism that could explain body mass fluctuations, despite captive bears being fed year-round (American black bears [ 30 ]).…”