THE IMPORTANCE OF SOCIAL LIFE 79 



There are many interesting leadership patterns in animals. 

 In some mammals the physically strong are the leaders, but 

 in others it may be an old female. The Scotland red deer 

 herd is usually led by an old female. The males in this 

 species sometimes challenge for leadership, but they flee 

 when danger comes, and the old and experienced female 

 goes back on the job. Baboons sometimes organize groups 

 of 80 to 100 individuals. Leadership here does not seem to 

 reside in one individual but seems to be divided among old 

 males who flank the herd and bring up the rear when the 

 colony is on the move. Baboons also post sentinels and are 

 said to send out scouts. Reindeer herds of great size show 

 considerable organization although no one individual has 

 ever been observed to be the definite leader. Among rein- 

 deer, quiet, weaker individuals are in the center of the herd; 

 restless, stronger individuals in the vanguard. Certain other 

 strong individuals are on the sides. Here there seems to be a 

 sort of sub-leadership with a possible dominant near the head 

 or at one side. With some mammals a jealous male, who drives 

 all other males out of the herd, takes over and is very defi- 

 nitely the leader. The leadership of older females in herds of 

 red deer, and of old males among primates and others, seems 

 to rest purely on the basis of experience and sagacity. Cer- 

 tainly, leadership does not always go to the more pugna- 

 cious, the stronger, or the faster. 



It may be that leadership or dominance in the societies of 

 birds and mammals rests on some genetic basis; i.e., genes 

 tending to determine such behavior. There is, however, no 

 morphological difference by which the dominant individ- 

 uals can be distinguished; there are no caste distinctions as 

 with the termites and Hymenoptera (wasps, ants, and bees). 



In termites, distinctions between reproductive individuals 

 and the workers and defenders of the colony are clear. The 

 king and queen of the termites are produced genetically, 

 probably by the usual X chromosome, but the other castes 

 do not depend on such segregation. Eggs develop into 



