An analysis of the observations made between 5:05 and 7:45 p.m. on this date provide the following 
table: 
Number of individuals active during the early evening 
Local affinity 
Number of 
ra f s pelage 
marked 
5:05-6:40 
p.m. only 
Both 
periods 
6:40-7:45 
p.m. only 
Neither 
period 
South half of pen 
18 
8 
2 
5 
3 
Beth sides of pen 
8 
3 
0 
3 
2 
North half of pen 
15 
0 
0 
3 
12 
Observations were terminated at 7:45 p.m. Presumably the majority of the 
rats living on the north half of the pen became active after the other rats 
became temporarily inactive. 
4. July 8, 1948 6 p.m. . . I have seen only two rats at the North Alley Burrow. Although there 
have been many passages in and out of the South Alley Burrow. 
5. July 9, 1948 5:50 p.m . . I just saw the first rat leave the North Alley Burrow, although a number 
have left or entered the South Alley Burrow. 
6. April 19, 1949 Although I have not recorded the presence or activities of all rats out during 
the past hour, there can be no doubt that females are much more active 
than males during these dawn hours. This is in striking contrast to the 
excess of males that were active at dusk. 
7. April 25-26, 1949 A portion of the population was pelage marked for distance recognition. 
There were two periods of observation. First: 10:45 p.m. to 2:30 a.m.; 
2d: 4 to 5 a.m. 
Period Active in Food Pen 
1st only Both 2d only 
Number of Males 8 7 6 
Number of Females 14 1 
At least for males this strongly suggests a time differentiation in the utiliza- 
tion of a common goal. 
The terminal group of observations, Nos. 8 to 17, concern rats known to be at the very bottom of the 
social scale at the time the observations were made. They reveal how such socially low ranking rats avoid 
their more dominant associates by becoming active during the more unfavorable (daylight) portions of 
the day or during the night when the other rats are resting in their harborages. 
Female 
Female 
10. Male 8 
1 1 . Male 8 
12. Male 8 
October 3, 1947; 2:19 to 2:44 p.m.; 324 days of age. Eating in Food Pen. 
October 24, 1947; 3 to 5:45 p.m.; 344 days of age. She was continuously 
active about Food Pen during this period when there were no other rats 
active. 
July 11, 1947; 267 days of age. 
Although observations were made continuously from 6:15 to 7:54 p.m., Male 
8 was only observed momentarily in the Food Pen at 7:28. Presumably this 
lack of appearance resulted from his avoidance of the other adult rats, most 
of whom were observed several times during this period. 
2:30 to 2:50 p.m.; October 9, 1947; 357 days of age. He made 11 trips from 
the Food Pen carrying garbage into Box 28. This storage of food will cer- 
tainly aid him in avoiding the dominant male 12. 
3:40 p.m.; October 21, 1947; 369 days of age. I le made several trips carrying 
garbage from the Food Pen to Box 28. 
1M 
