Table 50. — Colony j: Area IV burrow colony including Box 28, and burrow in West Alley 
Rat's number 
Place of birth 
Maturity 
index 
May 
weight 
May 
wounds 
Surviving young (16) 
Placental 
scars 
Males: 
82 
SAB 
1. 11 
542 
14 
89 •. . 
SAB 
1.15 
524 
20 
675 
SAB 
1.50 
480 
14 
677 
SAB 
1.67 
418 
862 
SAB 
11.79 
423 
5 
874 
Area I 
111.00 
402 
10 
436 
Area IV 
11.60 
400 
25 
Mean 
1.97 
456 
14. 7 
Females: 
477 
SAB 
11.80 
354 
1 
No 
18 
383 
SAB 
11.30 
409 
7 
Yes 
12 
697 
SAB 
1.50 
526 
4 
Yes 
17 
686 
NAB 
11.00 
482 
3 
No 
694 
NAB 
1.75 
440 
13 
No ... . 
62 
Area III 
1.81 
347 
21 
No 
3 
354 
Area IV 
11.25 
426 
7 
Yes. . 
19 
43 
NAB 
0) 
Mean 
11.06 
427 
7.5 
13. 8 
She is a senescent female too old to breed. 
Colony j: Area IV Burrow Colony including Box 28 and 
the Burrow in the West Alley ( table 50). 
Two of the 15 rats of this colony actually had 
very little association with the remaining 1 3. These 
were females 383 and 697 who were born at the 
South Alley Burrow. During the spring of 1949 
they established a burrow in the West Alley where 
each had a litter. This position brought them in 
closer association with the Area IV Burrow colony 
than with any other rats. In contrast to these two 
females, only one of the five nonsenescent females 
in the burrow opposite Box 28 in Area IV had a 
surviving litter, and this was the only one of the 
females which was born here. Whereas, birth at 
the South Alley Burrow favored reproduction, 
even elsewhere, it is important to note that the 
colony f S.A.B. female, who did not produce 
surviving young, was an extremely small, slow 
maturing individual. 
One line of evidence supporting the belief that 
colony f was lower ranking than colony e in Area 
III, was that it contained the senescent female 43 
and one of her adult progeny who had earlier been 
excluded by the rats invading Area 111 from the 
direction of Area IV. Even though a majority of 
the members of colony f were bom at the South 
Alley Burrow, this does not overly accentuate the 
status of this colony, since most of them were 
individuals who were excluded from their place of 
birth, and were unable to establish themselves in a 
more favorable locality. 
Colony g: Passage 4 burrow and its North Alley extension 
{table 51) 
and 
Colony j: North Alley Burrow {table 52). 
Although listed as separate colonies, their 
proximity and prior history require discussion 
together. See figure 22 which shows the details of 
their burrow system. A number of lines of evidence 
have been given which indicate a considerable 
stress having been placed on the rats living at the 
North Alley Burrow. This stress led to social 
disorganization. Members born there departed, 
while rats born elsewhere moved in. Coincident 
with this social disorganization the burrow began 
to disintegrate into isolated segments. By June 
1949 there was only one place in the burrow where 
an alternate route along tunnels was possible. 
210 
