1. The Social Use of Space 



91 



Production of young is fairly ineffective in small groups in comparison 

 with those containing 10 or 11 adults (Curve C, Fig. 32). In general, the 

 trend of young per female also decreases as groups get larger than 12 in- 

 dividuals. The two very large groups not included in this figure and which 

 had 27 and 31 adults were characterized by only 0.18 and 0.29 young per 

 female, respectively. We must conclude that group size does affect those 

 behaviors and physiology culminating in the production and survival of 

 young. 



UJ ■— 



2 Q. 0.10 



P < 0.05 

 o >. 



Vng/j 



Aa 



'''"' o° ^ ° ° ° ° °o , o „ - CO 



I 1 I I I I I I I 1 1 I I I I I 1 1 1 



5 10 15 20 



NUMBER OF ADULTS IN GROUP (HOWLER MONKEYS) 



Fig. 32. Group dynamics of howler monkeys based upon Carpenter (1962) . 



Another way of looking at this problem is to ask: "What proportion of 

 the total young are contributed by each group size?" For any group size 

 the proportion will depend upon (a) the proportion of females in the 

 group (Curve D, Fig. 32), (b) the number of young per female (Curve C, 

 Fig. 32), and (c) the number of groups of each size (Curve A, Fig. 32); 

 where such data for each group are weighed against similar data for all 

 other group sizes. Resultant data are given in Curve B, Fig. 32. This 

 curve clearly shows that more individuals gain their initial social experience 



