PHYSIOLOGICAL STUDIES OF THE RUFFED GROUSE 



765 



111 each group, tin- scxr.s witc oveiily ilividfd. The results (if the total |)erif)d of fast are 

 recorded in table 1 1 2. 



The ability to withstand fasting does not seem to be entirely dependent upon nor strictly 

 proportional to body size (weight) alone. Temperature factors appear to have been highly 

 significant in the case of the three female grouse which lost approximately .31 per cent of their 

 weight after fasting 189 hours at 40°F. 



The trend of daily weight change for individual fasting grouse in all groups is shown in 

 figure 92. Figure 93 shows the percentage of weight loss. The slopes of these curves are 

 interesting in several respects. They indicate that (1) the daily ingestion of water pro- 

 longed life and sustained body weight; (2) grouse of lower weight suffered a more rapid loss 

 in weight*; (3) heavier grouse had a tendency to maintain a more constant weight loss: and 

 (4) percentage losses in weight were more or less proportional to the hour of fasting. 



Sixty-seven per cent of the grouse in Group C, on test without food or water at 65°F., 

 died, on the average, at the 88th hour of fast, with an average loss of 16..5 per cent of the 

 initial weight. When this weight loss for Group C is compared with the average percentage 

 loss for Groups A and B at the same hour of fast, it was revealed that the latter had lost only 

 11.7 per cent of their initial weight. This small difference is highly significant since the 88th 

 hour of fasting with water represents only 40 jier cent of the total period of fasting to which 

 they were exposed. Undoubtedly this greater degree of resistance to fasting was due to the 

 ingestion of water by those birds that were allowed it during the test. 



The average distribution in weight loss ])er 24 hours showed the rate to be considerablv 

 less during the daytime than during the night, the greatest loss occurring from midnight to 

 8:00 to 9:00 a.m. 



TABLE 112. LOSS IN WEIGHT AMONG ADULT GROUSK DURING STARV.VTION ILNDICH DIFFERENT 



CONDITIONS 



The grouse subjected to fasting without drinking water a\ailable lost over twice as much 

 weight during the day as those that fasted with water available. It would be expected that 

 considerable loss in weight would be temporarily compensated for by the ingestion of large 

 quantities of water. The weight-sustaining properties of water are clearly indicated by these 

 data. 



The influence of water as a factor in sustaining life and retarding loss in body weight is 

 shown in figure 94. When these data are compared to data presented in table 112. it is 



In a later cx|ifiiiiu'iit. luiwcvt-r, lighter hinls were 



resistant to fasting, p. 772. 



