DIAMOND-BACK TERRAPIN CULTURE 
69 
the proper sex ratio present, which appears to be about one male to five females, at 
least 90 per cent of the eggs laid should be fertile. 
Great fluctuations in the death rate have taken place among the young animals, 
both among the ones that were kept warm and fed during the winter as well as among 
the hibernating lots. The cause of the deaths in the hibernating lots is not known, 
but in the winter-fed lots the mortality has been due principally to two causes, 
namely, a disease causing sores and to “soft shell.” The disease causing sores, 
which may be of bacterial origin, was not equally severe from year to year, and it, 
more than anything else, has caused fluctuations in the death rate of winter-fed 
animals. Soft shell is associated with a failure to eat, causing general emaciation 
and gradually the softening of the shell, frequently, although not always, followed 
by death. Soft shell also causes many deaths among terrapins after they emerge 
from hibernation, and it results in more deaths than all other losses combined in 
both groups of animals. 
The percentage of terrapins that were grown to maturity has been reduced 
materially in some of the lots on hand through depredations by rats while the animals 
were small, losses during storms, and apparently by escapes made by the terrapins 
because of their well-developed climbing propensities. 
Evidence is produced that would tend to show that about 60.7 per cent of the 
animals hatched may be grown to maturity and that winter feeding increases the 
rate of survival. 
Terrapins have an average length of about 27 millimeters at hatching. Young 
animals, when kept warm — that is, if placed in a brooder house — remain active 
during the winter, and the majority of them will begin to take food within a month 
or two after hatching. If the young are left out doors, they do not feed until they 
are 7 to 8 months old; that is, they go into hibernation soon after hatching or they 
remain in the nests in which they are hatched to hibernate, and they do not feed 
until the weather gets warm the following spring. 
Generally about 1 year’s growth was gained during their first winter by the 
recently hatched young when placed in the brooder house, in which the temperature 
was kept as far as possible at 80° F. or higher; that is, an average gain of growth (for 
all lots that had been fed the first winter) of 4.7 millimeters was made. The advantage 
in growth attained through winter feeding usually was retained and, furthermore, 
the winter-fed animals produced eggs a year earlier than the hibernating lots. 
Winter feeding, aside from its advantages with respect to earlier maturity when 
animals are grown in captivity, has the advantage of carrying the animals through 
the critical stages of life at an earlier age. When terrapin culture is engaged in for 
the purpose of rebuilding or augmenting the supply in nature, the winter-fed animals 
apparently are able to take care of themselves and stand just as good a chance of 
survival at an age of about 8 months as the hibernating ones do a year later. The 
earlier liberation reduces the amount of care necessary and presumably hastens 
returns. 
Some females reach a length of about 5 ){ inches and sexual maturity in 5 years; 
others require a much longer time to reach this size and stage in life. Evidence is 
produced that tends to show that some females never reach a length as great as 6 
inches. Males rarely exceed a length of 4 % inches. Data are presented that show 
