DIAMOND-BACK TERRAPIN CULTURE 
41 
was 28°. The highest temperature reached in 1923 was 66° and the lowest was 23°. 
None of these temperatures is regarded as unusual. The differences in the averages 
for the other months do not exceed 4°; nor are any of the daily temperatures regarded 
as excessively high or low. Certainly, if low temperatures were a detriment, the 
brood of 1917 would have perished, as the winter of 1917-18 was by far the coldest 
that has occurred during the course of the experiments (definite temperature records 
for this winter, unfortunately, are not at hand). The mortality records show, how- 
ever, that only 1 of 735 animals placed in hibernating boxes died that winter. The 
highest percentage of survival throughout the course of the experiments, then, 
appears to have occurred during an excessively cold winter and again (1926) during 
a moderate winter. Therefore, it is not evident that the fluctuations in winter tem- 
peratures as they have occurred at Beaufort in the years during which the present 
experiments have been under way have affected the death rate of young hibernating 
terrapins. 
The hibernating terrapins have been kept in winter quarters that have varied 
little, and the care has been about the same and in the hands of the same terrapin 
culturist from the beginning. It is evident, therefore, that the cause or causes for 
the pronounced differences in the death rate of various broods of young hibernating 
terrapins has not been found, and this subject remains for future investigation. 
Table 17 shows that in 9 of a total of 14 broods the percentage of terrapins that 
lived until they were removed from their winter quarters was greater among the 
hibernating terrapins than among winter-fed ones. However, the hibernating ones, 
as already stated, each year were taken from their winter quarters and counted 
four to six weeks earlier than the winter-fed lots. It has been pointed out elsewhere 
that the death rate usually has been quite heavy during the first several weeks after 
the terrapins emerge from hibernation and certainly much heaveir than in the winter- 
fed animals for the same period of time. Definite statistics are not available for 
comparison, but our terrapin culturist and the writer have not the slightest doubt, 
from their observations extending over several years, that by the middle of May, 
when the winter-fed terrapins usually were counted, the percentage of survival 
among them at that time, for all years combined, exceeded that of the hibernating 
animals. Furthermore, the winter-fed animals nearly all had gained some growth 
and thereafter had a much better chance to survive. A few comparatively large 
lots of terrapins have been retained at the laboratory during recent years, and 
although the records are marred by depredations wrought by rats, a far larger per- 
centage of the winter-fed lots than of the hibernating ones survived to reach an age 
of 1 and 2 years, and the deaths from natural causes certainly were much greater 
among the hibernating animals than among the winter-fed ones. 
The early broods (1910 and 1911) carried to maturity in captivity, as indicated 
in a preceding paragraph, appear to show that winter feeding, from the standpoint of 
survival, has a slight advantage. Later records (if they were not clouded with missing 
animals killed and frequently carried away by rats), it is confidently believed, would 
show a much greater advantage in winter feeding than the early ones. Our terrapin 
culturist and the writer are both firmly convinced (although they are unable to supply 
