Unexplained Death of a Black Bear

Explaining sudden unexplained death.

Biochemical Variation in the Black Bear

A total of 35 presumably distinct biochemical loci were analyzed in black bears (Ursus americanus) from Alaska, California, Maine, Montana, Tennessee, and Virginia by using starch-gel electrophoresis. Limited spatial subdivision of gene frequency was observed in Tennessee. Overall heterozygosity levels are lower in black bears than would generally be expected for mammalian species. Levels of in...

The urothelium of a hibernator: the American black bear

The American black bear undergoes a 3-5 month winter hibernation during which time bears do not eat, drink, defecate, or urinate. During hibernation renal function (GFR) is 16-50% of normal but urine is reabsorbed across the urinary bladder (UB) urothelium thus enabling metabolic recycling of all urinary constituents. To elucidate the mechanism(s) whereby urine is reabsorbed, we examined the UB...

New Year's Resolutions and the Black Bear.

American Association for the Advancement of Science Science serves its readers as a forum for the presentation and discussion of important issues related to the advancement of science, including the presentation of minority or conflicting points of view, rather than by publishing only material on which a consensus has been reached. Accordingly, all articles published in Science-including editor...

Leucine Metabolism in the Black Bear

Metabolism of the essential amino acid leucine was studied in 3 black bears (Ursus americanus) in February while the bears were denning and not eating or drinking and in May while they were eating and drinking normally. (U-4C) leucine was injected as a bolus intravenously, and timed samples of venous blood were obtained over an 8-day period. Total activity in plasma gradually increased in Febru...