avoiding male 49. He remained near the place of 
his birth in Area II in close association with his 
mother, No. 44, into January 1949. At about the 
same time she shifted her place of residence back 
into the South Alley Burrow. However, she 
remained with the lower ranking colony inhabiting 
the burrow in the South Alley near Passage 2. 
At this point the question may be raised as to why 
this male, who was born in Area II, became the 
dominant male with a harem of 13 females at the 
South Alley Burrow, rather than any of the many 
males born there during 1948. I believe that there 
are three major contributing conditions or situa- 
tions. First, male 49 was one of the only four males 
whose growth was so rapid that at every capture 
he fell into the Maturity Index Channel I, and only 
three of these males survived through the 1949 
spring breeding season. Second, because of his 
close ties with his mother, his shift in place of 
residence back to the South Alley Burrow may 
have influenced her return to the South Alley. 
Three, conditions about the South Alley Burrow 
during 1948 were unfavorable for males born there 
remaining. 
Table 43. — Data concerning the males who were born 
at the South Alley Burrow during 1948 and who sur- 
vived longer than 150 days 
Litter number 
Date of birth 
(1948) 
Number of 
males sur- 
viving longer 
than 150 days 
Average 
maturity 
index 
7 
Mar. 7 
6 
1.26 
10 
Mar. 16 
5 
1.79 
14 
Apr. 30 
1 
11.14 
17-19 
May 18 
8 
1.50 
22a 
June 1 
1 
1.83 
25b 
July 15 
5 
11.30 
32 and 37 
Sept 
3 
29 
11.62 
An understanding of why this was so may be fa- 
cilitated by examining table 43. It will be seen 
that the timing of the litters was such that by the 
time each reached approximately 60 days of age 
some other female than their mother was lactating 
at the South Alley Burrow. Thus, these males were 
becoming independent of their mother just at the 
time when they were most likely to receive psycho- 
logical drubbings from these lactating females. 
This and the competition among the males as they 
matured exerted pressure to disperse. The males 
born at the South Alley Burrow during March 1948 
were captured or observed between June 19 and 
July 31, 1948, 40 times at the South Alley Burrow 
and 54 times elsewhere. Actually, the amount of 
dispersal was greater than these records indicate 
since observations of movements produced a pat- 
tern of residence elsewhere, particularly Area IV, 
with rather frequent return visits to the place of 
their birth. These induced shifts in place of resi- 
dence are shown in figures 114 and 116. Toward 
the end of the summer of 1948 conditions of com- 
petition had become so severe that there was an 
inhibition of growth to the extent that none of the 
later born males could offer effective competition 
to those born earlier. 
Thus, by the winter of 1948-49 the situation of 
the South Alley Burrow was one of inhabitance by 
several females who were born there and who 
formed a rather stable group despite the lack of 
permanent residence of any males. During the 
latter portion of this winter, old female 44 and five 
(males 49 and 707, and females 48, 875, and 925) 
of her nine surviving progeny moved from Area II 
into the burrow by Passage 2 in the South Alley. 
Due to his proximity to the South Alley Burrow 
and because all males who were large enough to 
offer him any serious competition had long since 
developed attachments elsewhere, it was only nat- 
ural that male 49 should assume territorial defense 
of the South Alley Burrow as soon as some of these 
females came into estrous during the latter part of 
February 1948. He and these 13 females formed 
the colony of highest social status of the entire 
population (colony a, pp. 204 to 205). 
One of the other two surviving males, No. 690, 
whose growth was so favorable as to have always 
been classified in Maturity Index Channel I as- 
sumed control of Area I, which was the second 
most favored area through the history of the pen. 
Along with two other (males 82 and 74) and slightly 
smaller of his five brothers, he remained mostly at 
the place of his birth, the South Alley Burrow, well 
into his 4th month (June 1948). Their remaining 
here was probably attributable to their remarkably 
rapid growth. At 1 13 days of age (June 30, 1948) 
male 690 was seen to follow the dominant female 
of Area I, No. 28, into Area I. However, he 
remained as a marginal member of this Area I 
colony until the death of the then dominant male of 
Area I, No. 22, sometime during December 1948. 
200 
