Hematology of the brown bear (Ursus arctos) from southwestern Yokon Territory, Canada.

Abstract

Blood samples from 22 brown bears (Ursus arctos) and 5 black bears (Ursus americanus) were examined for erythrocyte count, erythrocyte morphology, erythrocyte diameter, hematocrit, hemoglobin, erythrocyte indices, serum iron, total iron-binding capacity, leucocyte count, and leucocyte differential count.A statistically significant decrease in erythrocyte count and hematocrit and increase in erythrocyte indices was found in brown bears from spring to summer. Limited evidence suggests that the spring to summer change may be reversed in the fall.No differences were apparent between sexes at any season but it was indicated that young bears had lower red blood cell concentration, lower hematocrit, and lower hemoglobin concentration than other animals.Leucocyte differential counts in the study were similar to those reported for other bears. Anisocytosis with numerous spherocytes and burr cells characterized the erythrocytes.Serum iron and total iron-binding capacity varied but did not suggest iron-deficiency anemia.Hematology results for the black bears were similar to those of brown bears but our small sample did not allow an investigation of seasonal changes in the species.