immediately ran into the gathering sack, 
as soon as the door of the trap was opened, 
these rats had to be shaken into the sack. 
Items 1 to 3 pertained primarily to those individuals 
which became social outcasts sometime between 
weaning and the time of physiological sexual 
maturity at about 115 days of age. The remaining 
items pertained to most social outcasts regardless 
of the age at which they became outcasts. 
4. Marked diurnality of activity or the rat 
became active during those periods of the 
night when most other rats were temporarily 
inactive (see pp. 112 to 135). 
5. Tendency to approach hesitantly or retreat 
from nonoutcast rats. It is presumably by 
such behavior as this that the outcasts 
elicit frequent attacks upon them by other 
rats (see pp. 179 to 180). 
6. Tendency to repeatedly approach and then 
withdraw from the Food Pen without 
entering, it, even when no other rats were 
active (see pp. 179 to 180). 
7. In the Food Pen they frequently took a pellet 
of food over into one corner to eat. This was 
never observed for any of the nonoutcast rats. 
8. Nonharborage food cache formation 
(see pp. 102 and 106 to 109). Outcasts 
would come into the Food Pen, when no 
other rats were about, and transport pellets 
to one or more places within the Food Pen. 
These were usually deposited in piles either 
under the platforms to the activity recorders 
or just out on the bare ground. The most 
extreme case was for a rat which made a 
number of consecutive trips taking pellets 
from the base of the hopper, climbing up the 
side of the hopper, and depositing them on 
top of the mass of pellets inside the hopper. 
After completing such a period, these in- 
dividuals would depart for their place of 
harborage, even though no other rats were 
about. 
9. Marked tendency to harbor in unfavorable 
situations. (See account of males 97 and 662, 
p. 185, and female sibs 17, 20, and 25, pp. 193 to 
195, and colony k, p. 213.) By unfavorable is 
meant that the place of harborage was farther 
from the food source or was more exposed to in- 
clement weather such as a collapsing burrow, or a 
harborage box whose sides had rotted through. 
10. Formation of nonreproducing aggregates (see 
tables 56 and 57, and discussion of colonies g 
to k, pp. 210 to 213). The aggregates 
were nonreproducing in the sense that they 
were usually composed mostly of males. The 
females present were either never seen to be 
courted by males, or if they conceived they 
failed to rear young, nor were the males 
from the all male groups seen to participate 
in the sexual attention toward females in 
estrous in neighboring colonies. The only 
instance of homosexual behavior, involving 
two males, was for one of these aggregations 
of outcasts. 
Only the members of one litter were characterized 
by item 8 as well as the first three items of this 
syndrome. This was Litter 13 (see section on the 
history of the “Three Litters of Female 43,” 
pp. 147 to 148). This was the only litter born in 
the pen which was conceived on the date of par- 
turition of a previous litter, and which during their 
nursing period was subjected to competition from 
older sibs. Female 7, the smallest of the intro- 
duced rats, and male 83, a low-ranking, average- 
growing male born at the North Alley Burrow, 
were the only two other rats to be observed as 
adults engaging in the aberrant type of storage 
indicated in item 8. 
Male rats which as adults might have been domi- 
nant, or at least had matured under such favorable 
conditions as to engage in competition for dominant 
status, eventually were characterized by this syn- 
drome of the social outcast. The introduced male 
12, who was dominant during the summer and 
fall of 1947, was such an example. The males 
which had a better than average growth rate, and 
which became members of colonies h to k (pp. 212 
to 213) were also individuals which exhibited 
this transition in behavior to that of the social 
outcast as a result of their unsuccessful attempts to 
attain favorable status. 
G. Locality of Birth and Social Status. From time 
to time through this account of the history of this 
experimental population, mention has been made 
that rats born in the southeast half of the pen held 
higher social status than those born in the north- 
west half (see especially pp. 38 to 41, 117 to 
123, 138 to 143, 164, 186). In order to learn more 
of the effect and implication of this social stratifica- 
tion a tabulation was prepared (sec table 42) of all 
combats for which there was a decisive termination. 
However, this tabulation is relatively meaningless 
196 
