Figure 39. — Details of the balls of mud that have been formed and pushed into place at the South Alley Burrow hole 18. 
Photograph by U.S. Army Signal Corps. 
there lay a comparable amount of space (the 
East and West Alleys and Areas II and IV) in 
which few animals were born and in which the 
residents were from both of the two breeding 
areas. From table 2 it may be seen that there 
were only 1 5 burrow sealings in the south quadrant 
of the pen with its more favorable social structure 
while there were 46 in the north quadrant with 
its more unfavorable social structure. One might 
assume that the difference in frequency was 
purely a result of the difference in the total usage 
of the two regions. However, I am of the opinion 
that the total usage of these two regions was 
essentially identical. Although there is no way 
of conclusively proving this, figures 106 to 116 
record a representative sample of captures within 
each of these regions: 422 in the south quadrant 
and 415 in the north quadrant. With this near 
identity in usage of the two regions (Chi square = 
0.0583) which might be anticipated to occur 8 
times out of 10 on a pure chance basis there is no 
evidence for a differential usage of these two sides 
of the pen. 
Differences in frequency of lactation in the two 
regions is also not likely a factor in explaining the 
difference in the frequency of the burrow sealing 
behavior in the two regions. In fact one might 
expect an opposite difference in the frequence of 
the burrow sealing behavior had lactation largely 
influenced it (see table 3) since more young were 
reared in the south quadrant. 
39 
