Seasonal Variations in the Hematology and Physiology of Black Bears

Abstract

During 1956 and 1957, four black bears (Ursus americanus) were held captive in northern Michigan. They were dormant in winter quarters from approximately 25 December to 17 April, during which time all lost weight. Four times over a 9-month period the bears were anesthetized and various physiological and hematological values were obtained.