42 
BULLETIN OF THE BUREAU OF FISHERIES 
definite statistics) that a much larger percentage of winter-fed than of the hibernat- 
ing terrapins (if both were retained in equal numbers) would survive to reach an 
age of 2 or 3 years. Thereafter, as shown elsewhere (Table 19), the death rate is 
small. Winter feeding, even though considered only from the standpoint of sur- 
vival and entirely aside from the faster growth and earlier maturity, undoubtedly 
is advantageous. 
The percentages of survival of most of the lots of terrapins that were hatched and 
raised, or partly raised, in captivity are shown in Table 18. In this table “missing” 
terrapins are counted as dead, and the percentages are based upon the surviving ones 
only. In next to the last column is given (except in those lots in which the terrapin 
were carried through from hatching to maturity without selection and without remov- 
ing any of the original number) the percentage of the whole lot that probably would 
have survived had they been retained. In making the calculations it is assumed that 
equally as large a percentage of the entire broods or lots from which selections were 
made would have survived, had they been kept in captivity, as of the smaller lots 
selected. This appears to place the probable averages of survival a little too high, 
because in most instances the largest and finest animals were retained. The probable 
percentage of survival at 6 years of age (when at least some of the animals had 
reached sexual maturity) for all lots combined is 60.7. If depredations by rats could 
have been avoided, the average percentage of survival undoubtedly would have been 
considerably greater. It is quite certain, also, that in a plant built in the light of the 
knowledge gained from the experiments conducted and constructed especially for 
terrapin growing a somewhat better average could be attained. On the other hand, 
the average of 60.7 per cent of survival apparently compares favorably with results 
obtained in chicken farming. (See Hildebrand and Hatsel, 1926, p. 15, footnote.) 
It was stated in the first paragraph of this section that accurate records of deaths 
are not available. However, after a terrapin has reached an age of 3 years or more 
it is of a sufficiently large size that a dead one in a pen scarcely would be unnoticed. 
Table 19, giving the number of terrapins at 3 years of age in various lots held in con- 
finement, together with the deaths that were noticed during their third year and 
thereafter until disposed of or last counted, nevertheless appears to be of interest. 
It is evident at once that the death rate has been consistently low. Generally it was 
impossible to determine the cause or causes of the deaths that have occurred among 
the larger terrapins. 
The low death rate (see Table 19) that has occurred among the wild brood stock 
is noteworthy. Some of these animals were confined in 1909, others in 1911, and a 
few appear to have been held over from certain experiments conducted in 1902. 
Most of these animals were mature when confined, but not all of them, as stated by 
Barney (1922, p. 94) and Hildebrand and Hatsel (1926, p. 13). Measurements of 
the first lot of breeders, taken when purchased in Beaufort in 1909, have been found 
recently among the early records, and these show that 10 of 45 females obtained 
in this lot were less than 5 inches long and therefore almost certainly sexually imma- 
ture. The second lot of breeders, bought in 1910 and 1911, also appears to have con- 
tained at least 6 of a total of 43 females that were less than 5^ inches long. It 
seems to be incorrect, therefore, to say that all the wild terrapins were mature when 
