Stress Response and Survival Time in Three Wildlife Species

Abstract

The need for studies on the ability of various wildlife species to survive and the factors affecting their survival has become increasingly important in wildlife management research. Such information is not only essential for an understanding of population behavior but also for planning habitat improvement programs designed to meet specific requirements. One approach toward obtaining physiological information of this type is by subjecting an animal to an applied stress and measuring its resistance and survival time. Kabat, Meyer, Flakas, and Hine (1956) in Wisconsin carried out a series of experiments throughout the year on hen pheasants (Phasianus colchicus torquatus) in which they subjected the birds to the artificial stress of caging and starvation and measured the birds' resistance in terms of body-weight loss and body-temperature decline. The design of their studies was based on Selye's (1949) hypothesis that adaptation to a specific stress (such natural stresses as egg laying, molting, etc.) lowers the body's resistance to different stress to which the animal is not adapted. The applied stress, therefore, was used as a means of demonstrating whether there was seasonal variation in adaptation energy, and which of the naturally occurring physiological stresses caused the greatest decrease in resistance. These studies showed that the use of this technique appeared to produce reliable trends in stress resistance and survival time. There was variation in the hen pheasant's ability to survive the applied stress at different times of the year; this variation in stress resistance and survival time, furthermore, was related to the physiological condition of the hen. The hen pheasant studies opened the door to much more investigation along these lines. During the course of the Wisconsin pheasant experiments in January to March 1951, single tests were run on Hungarian partridge (Perdix perdix), chukar partridge (Alectoris graeca chukar), and cottontail rabbits (Sylvilagus floridanus). The purpose of this report is to present the results of these tests in order to document the data and provide background information for other investigators contemplating similar studies.