Hematological characteristics of grizzly bears (Ursus arctos) in central and northeastern Alaska

Abstract

Eighty-five grizzly bears (Ursus arctos) were captured during 1981 and 1982 in the Alaska Range and in the Arctic National Wildlife Refuge, located in the Brooks Range, Alaska. Blood samples from these bears were examined for erythrocyte count, leukocyte count, hemoglobin, hematocrit, and erythrocyte indices. Erythrocyte count, hemoglobin, hematocrit, and mean corpuscular volume were significantly higher in the first of two samples collected 1 h apart. This difference suggsts a response to stress during the capture by splenic contraction to provide an increased oxygen supply to oxygen depleted muscle tissues, followed by splenic relaxation and decreased blood pressure with expansion of blood plasma volume. Leukocyte count was significantly higher in the second sample. This difference was probably a result of neutrophilia caused by tissue damage from darting and the removal of muscle tissue samples. Alaska Range bears exhibited higher values for all characteristics except mean corpuscular volume and mean corpuscular hemoglobin, indicating that these bears were more stressed by their capture than bears in the Arctic National Wildlife Refuge.