Colony d: Area II, except Box 10 ( table 47) . 
Why so few rats inhabited Area II during the 
spring of 1949 is somewhat of a mystery. The 
following train of events certainly contributed to 
their absence. During the winter, until mid- 
January, female 44, who had been the dominant 
female of the whole pen, and her 600 gram son, 
No. 49, who was becoming the dominant male of 
the whole pen, lived here. Their presence prob- 
ably kept down the invasion to five rats. Actual- 
ly, three of these were hardly invaders. They were 
Area III rats which had lived with the young of 
female 44 since they were juveniles. None of 
female 44’ s young, bom in Area II, were still here 
with her. The migration of female 44 back toward 
the South Alley Burrow in late January along with 
six of these nine young of hers, including male 49, 
left Area II without any controlling individuals. 
In fact, once these two rats left all the remaining 
rats also soon left Area II. Practically no rats were 
observed here during February and March. Up 
until mid-April - female 75 was residing in the 
adjoining Area III, where she had moved earlier 
from Area IV with her three surviving adult prog- 
eny. She moved over into Area II about April 18, 
when she had her litter in Box 13 burrow. See 
page 202 for comments concerning male 95. 
Table 47. — Colony d: Area II ( except box 10), April-May 1949 
Rat’s number 
Place of birth 
Maturity 
index 
May 
weight 
May 
wounds 
Surviving young (9) 
Placental 
scars 
Males: 
95 
SAB 
1.50 
11.00 
472 
490 
13 
0 
751 
Area II 
Mean 
1.75 
481 
6.5 
Female: 75 
SAB 
Yes 
1.00 
644 
8 
i 16 
1 Includes the scars of the pregnancy upon last handling before shipping her to the National Institutes of Health. This 
second litter was born in transit to NIH. 
Colony e: Area III ( see table 48). 
The most striking thing about colony e was 
that none of the 14 rats born in Area III during 
1948 and which survived to May 1949 still lived 
in Area III. Ten out of the 16 rats born in Area 
III and alive to mid-January 1949 still resided in 
Area III. All were excluded by the beginning of 
the breeding season in March 1949. Five of the 
surviving males became members of the lowest 
ranking and all male colony k. A sixth, and largest 
of the Area III born males became a member of 
colony j. The seventh surviving male, 59, although 
apparently, in a more favorable situation than his 
sibs, that is in colony g, was functionally an asexual 
runt. Although none of the Area III born females 
produced surviving young from March through 
May 1949, their dispersal is instructive (see table 
49). 
The point of interest is that the more inhibited 
was their physical maturation, the lower was the 
social rank of the colony they joined after being 
excluded from Area III. 
Even as the replacement of Area III born rats 
began to occur, principally by Area IV rats, there 
was local segregation within Area III. In F ebruary 
1949 the two local colonies living in burrows 
leading from Boxes 23 and 25 illustrate this. 
Among the 16 rats in Box 23 burrow there were 
four of the to-be-excluded Area III rats (female 
43 and three of her progeny), but only two of the 
invading Area IV rats. In contrast to this, six of 
the nine rats in the adjoining Box 25 burrow were 
Area IV invaders (females 37 and 75 and four of 
their progeny), while there were no Area III rats 
here. See figure 129 with its indications that the 
Box 23 Burrow rats were the lower ranking of the 
207 
