SULKIN AND ALLEN 



The body temperatvire of resting bats has been shown to parallel 

 closely that of their environment over a range of 2° C to 30° C, and 

 the metabolic rate of these animals varies directly with their 

 body temperature (Hock, 1958). 



Data have been accumulated comparingthe course of experimental 

 viral infections in bats held at 5° C or 10° C with groups held at 

 24° C or 29° C and with groups held at low temperatures for a 

 period of time and then transferred to room temperature (24° C) or 

 29° C (Sulkin et al., 1960), Animals held in the cold become torpid 

 within hours of being placed at the low temperature, and we have 

 on occasion determined the rectal temperature of a number of cold- 

 adapted bats and found it to be quite close to ambient. On the other 

 hand, we cannot be positive that animals held at 24° C or 29° C 

 maintained constantly body temperatures equivalent to their environ- 

 ment. For a period of time following the handling associated with 

 virus inoculation and transfer to experimental cages, the bats 

 appear excited and are quite active in moving about their cages. It 

 is likely that during this period the animals have body temperatures 

 well above ambient. Within a day or so, however, they become quiet 

 and hang in groups in their cages; they are seldom seen moving 

 about except in the evening when they come down to the floor of the 

 cage to receive the food and water offered daily. There is doubt- 

 lessly considerable variation among body temperatures of individual 

 bats at these higher temperatures, depending on their degree of 

 activity. The difficulties inherent in recording individual body tem- 

 peratures on large numbers of infected bats precludes the possi- 

 bility of obtaining such data. In this presentation we will be com- 

 paring the course of viral infection in animals whose body tempera- 

 tures we know to be low (ambient temperature 5° C or 10 C) with 

 the course of the infection in animals whose body temperatures we 

 feel must have fluctuated between ambient (24° C or 29 C) and 

 possibly 36° C or higher (Morrison, 1959). 



Early in these studies it became apparent that animals collected 

 during the fall or early winter months survive for longer periods of 

 time in the cold than animals obtained in the spring or summer 

 months. Subsequently, these experiments were initiated only in the 

 fall, even though they could onlybe repeated or extended on a yearly 

 basis. Furthermore, a recent report by Menaker (1962) indicates 

 that the state of h3TDothermia achieved with summer bats is not 



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