Showing papers on "Animal mortality published in 1985"

Pulmonary physiological and surfactant changes during injury and recovery from hyperoxia.

Abstract: The time course of lung injury and recovery from a sublethal exposure to 100% O2 was investigated in adult rabbits. Animals were exposed to 100% O2 for 64 h and then returned to room air for varying periods of time up to 200 h. By the end of the exposure period, the alveolar permeability to solute increased significantly, and biochemical analyses of bronchoalveolar lavages showed a 30% decline in phospholipid content and a threefold increase in protein levels. However, other parameters such as wet-to-dry lung weight ratios, blood gas values, and pressure-volume mechanics were not significantly different from control levels after 64 h of hyperoxia. Twenty-four hours postexposure, alveolar phospholipid levels had declined even further (51% of control), and mean protein levels in lavage increased to eight times control values. These lavages exhibited severely impaired dynamic surface activity at 37 degrees C and 100% humidity in an oscillating bubble apparatus. In addition, total lung capacity, lung compliance, and arterial O2 partial pressure declined greatly at this time. Between 12 and 48 h postexposure, animal mortality was 35%; the remaining animals survived, and physiological parameters returned to normal by 200 h postexposure. Bronchoalveolar lavages from the recovered animals contained protein levels equal to those of controls and phospholipid levels approximately twice those in control lavages. Lavage surface activity also returned to normal by the 200 h postexposure time point.

Mortality Rates of North American Bears

Abstract: The age structures of 39 populations of three species of North American bears were analyzed. Estimated mortality rates of cubs in their first year were 30-40% for brown bears and 25-30% for black bears. Apparent subadult mortality rates derived from living animals (15-35% annually) were higher than those of adults. Apparent mean annual mortality rates of subadult and adult females combined were 17.2, 16.8, and 18.8% for black, brown, and polar bears respectively. Comparable values for males were 25.5, 23.0, and 22.6% annually. Because hunting appears to be the major mortality factor in most North American bear populations, interpretation of age structures is facilitated by explicitly incorporating the effects of hunting and its associated biases in the analyses. The simple model proposed to accommodate the hunter-bear interaction clarifies differences in age distributions between species and between sexes within species. Most of the differences in sex-specific mortality rates are a product of differential vulnerability related to home range size and method of hunting. Key words: age distribution, bears, mortality rates, North America, sex ratios, Ursus species