DIAMOND-BACK TERRAPIN CULTURE 
67 
Texas females) hatched in 1920. The two lots of the 1911 brood originally consisted 
of two groups of 100 each of unselected animals. When last counted (1927), 163 of 
these terrapins were found, all of them being females; nor has a male ever been 
noticed among these animals. 
The lot of hybrid terrapins to which reference was made in the preceding para- 
graph originally consisted of 100 animals selected at 8 months of age. This lot, when 
last counted (1927), consisted of 60 terrapins, of which 40 were males. It appears 
to be of interest to note further that a somewhat similar abundance of males prevails 
among the only other two lots of hybrid terrapins (both hatched in 1919) on hand- 
One of these is the product of Texas males crossed with Carolina females, and it 
originally consisted of 80 unselected animals. When last counted (1927), 52 of these 
terrapins were found, and 33 of them were males. The other lot at first contained 
100 selected animals, the offspring of Carolina males crossed with Texas females. 
This lot, due largely to depredations by rats when the terrapins were small, has been 
reduced to 31, and of these 18 are males. The greatest abundance of males in pure 
stock occurs in a selected lot originally consisting of 100 young, now (1927) reduced 
to 74, of Carolina terrapins hatched in 1919, in which there are 22 males. In all 
other lots of pure stock the males are in an even smaller minority. 
These data would appear to indicate that cross-breeding Carolina and Texas 
terrapins tended to increase the proportionate number of males. However, the lots 
are too small to justify that conclusion, and until more information is obtained it may 
be assumed that the present results are a mere coincidence. 
Table No. 36 shows in detail the sex ratio existing among the several lots of 
terrapins grown in captivity. The lots appear to be sufficiently large and numerous 
to justify the conclusion that a considerably larger number of females than males 
may be expected to reach maturity in terrapin farming. This is important from a 
practical viewpoint, as the females reach a relatively much larger size than males 
and have a correspondingly greater value on the market. As stated elsewhere, no 
definite information relative to the natural sex ratio in terrapins has been gained. 
A few lots of young animals are on hand, however, which may help to cast some 
light on this problem when they reach a sufficiently large size to admit of the recog- 
nition of the sexes. 
If it were assumed that the usual 1 to 1 ratio prevails among young terrapins, 
then it would follow that the males simply fail to reach maturity. The selection of 
the larger and stronger animals at about 1 year of age, as was often done, does not 
appear to have resulted in constantly choosing females in preference to males. If 
it had, then it might be reasonable to expect the males to be in the majority among 
those terrapins that were chosen because they were small and undersized. This 
does not appear to be the case, however, for a lot of 100 terrapins of the 1912 brood 
was selected at 1 year of age as the very poorest and smallest among several hundred 
animals. When last counted (1927), 64 animals were found and among them were 
only 10 males. In unselected groups of Carolina terrapins the males, too, are greatly 
in the minority. 
The supposition that the males failed to mature is complicated by the fact that 
the number of males present at maturity in some of the unselected lots as well as 
selected ones, added to the total number of animals that died (assuming that the loss 
consisted wholly of males), still would not make a sex ratio of 1 to 1. 
