44 
BULLETIN OF THE BUREAU OF FISHERIES 
Table 18. — Actual and probable percentage of survival of terrapins at 6 years of age 
Brood 
Terra- 
pins 
origi- 
nally in 
brood 
or lot 
Number 
surviv- 
ing when 
selec- 
tions 
were 
made 
(usually 
at 8 or 9 
months 
of age) 
Number 
selected 
and 
retained 
Per cent 
of lots 
retained 
surviv- 
ing at 
6 years 
of age 
Probable 
per cent 
of whole 
brood 
or lot 
surviv- 
ing at 
6 years 
of age 
1910 
173 
0 
(>) 
83.2 
1910 
120 
78.3 
1911 
100 
> 
82.0 
1911 
100 
(i) 
78.0 
1912 
500 
463 
100 
93.0 
86.1 
1912 
500 
463 
100 
69.0 
63.9 
1913 
525 
504 
100 
92.0 
88.3 
1914 
1,349 
661 
100 
91.0 
49.0 
1915 
703 
0 
51. 1 
1916 
2,006 
1, 710 
200 
97.5 
83.1 
1917. 
1, 481 
910 
200 
50.5 
34.4 
1918 
1919. 
2,433 
1, 938 
100 
78.0 
63.9 
1919 . 
214 
0 
61. 2 
1919. 
300 
0 
31.0 
1920 
2,503 
1, 995 
337 
62.0 
52.7 
Average 
2 60.7 
Remarks 
All fed first winter and in part the second. Entire lot 
retained. 
Hibernating lot, all retained. 
Fed three winters. 
Hibernating each winter. 
Largest (best) selected from entire lot. 
Smallest (runts) selected from entire lot. 
Largest selected. 
Do. 
Missing, 84; probably escaped or carried away by rats or 
other enemies. This lot was liberated when 5 years of 
age. 
Largest selected. 
Largest selected; many missing. 
All liberated soon after hatching. 
Largest selected. 
Hybrids; Texas male, North Carolina female. 
Hybrids; North Carolina male, Texas female. Rats 
destroyed many during first year. 
Largest selected, three lots combined. 
1 No selection. 
2 In computing this average, the actual number of terrapins that survived in the unselected lots, as well as the number esti- 
mated that would have survived of the lots and broods from which selections were made, were taken into consideration. 
Table 19. — Deaths among adult and growing terrapins after an age of 3 years was attained 
Lot 
On 
hand 
3 years 
old 
Last 
counted 
Deaths 
during 
inter- 
vening 
period 
Missing 
at end 
of 
period 
Lot 
On 
hand 
3 years 
old 
Last 
counted 
Deaths 
during 
inter- 
vening 
period 
Missing 
at end 
of 
period 
1910 — 
157 
1925 
13 
14 
1917— Wide range 
63 
1927 
3 
21 
1910— Hibernated 
96 
1925 
5 
0 
1919 — Hybrids; Texas male, 
1Q11 — Fftd 
84 
1926 
6 
0 
Carolina female 
54 
1927 
1 
1 
1911 — Hibernated. 
81 
1927 
2 
3 
1919 — Hybrids; Texas fe- 
96 
1927 
6 
6 
males, Carolina male 
31 
1927 
0 
0 
79 
1927 
3 
12 
1919 — Domestic stock 
87 
1927 
1 
12 
1913 — Selected 
94 
1927 
9 
6 
1920— Hybrids; Carolina 
96 
1926 
7 
4 
males, Texas females 
64 
1927 
1 
6 
440 
1920 
20 
82 
1920 — Domestic stock 
144 
1927 
6 
24 
1916— Selected ... 
195 
1927 
6 
0 
Adults— Wild stock, age un- 
1917— Close range 
52 
1927 
1 
0 
known 
1 154 
1927 
9 
2 29 
1 On handjn 1911. 5 Mostly sold. 
RATE OF GROWTH 
The average length of diamond-back terrapins at hatching is about 27 milli- 
meters ( 1 X 2 inches), the usual range in size being from 25 to 30 millimeters. Occa- 
sionally individuals are hatched that are only 22 to 24 millimeters long, and there 
is a record of one abnormally small one with a length of only 19 millimeters. The 
largest one of which we have a record was 31.5 millimeters long. 
Newly hatched terrapins do not feed immediately. Those that are left outdoors 
to hibernate, as in nature, do not take food until they are from 7 to 8 months old; 
that is, they do not feed in the autumn during which they are hatched. In fact, 
