Weights and hematology of wild black bears during hibernation.
We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.
DelGiudice
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Research Service, U.S. Veterans Affairs Medical Center, Minneapolis, Minnesota 55417.
Rogers
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Allen
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Seal
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D000367:Age Factors; D000818:Animals; D001835:Body Weight; D004906:Erythrocyte Count / Q000662:veterinary; D004909:Erythrocyte Indices / Q000662:veterinary; D005260:Female; D006400:Hematocrit / Q000662:veterinary; D006454:Hemoglobins / Q000032:analysis; D006605:Hibernation / Q000502:physiology*; D007774:Lactation; D007958:Leukocyte Count / Q000662:veterinary; D009752:Nutritional Status; D012016:Reference Values; D001503:Ursidae / Q000033:anatomy & histology / Q000097:blood / Q000502:physiology*
D006454:Hemoglobins