414 



POPULATIONS 



between strangers was approximately 2 per 

 cent in contrast with freedom from moult, 

 amount of male hormone present, and so- 

 cial rank in the home flock, each of which 

 respectively "determined" 26, 22, and 6 

 per cent of success (Collias, 1943); White 

 Leghorn hens also dominate hens of other 

 breeds that are decidedly heavier individ- 

 uals (Potter, 1947). 



4. The location of the first meeting is 

 often important since many animals fight 

 best in or near their home territory. 



5. In strange territory, an animal ac- 

 companied by others from the home flock 

 or horde often wins from a stranger more 

 easily than if alone. The association of ac- 

 quaintances may be more important than 

 being within the home range (Doughs, 

 1948). _^ 



6. Animals with young, especially fe- 

 males with young, tend to fight more 

 fiercely than at other times. 



7. Males usually dominate females, par- 

 ticularly in those species in which the male 

 is the larger and showier sex ( Schjelderup- 

 Ebbe, 1935). Often there are two rank- 

 orders in a bisexual group, one for the 

 males and another for females, and these 

 scarcely overlap (Carpenter, 1942). 



8. The amount of male hormone present, 

 within an indefinite physiological range, 

 often increases social dominance of either 

 sex. The sexual component of the drive for 

 dominance in sword-tail fishes (Xipho- 

 phorus) may be distinguished from the so- 

 cial drive by gradual cooling; the sexual 

 appetite was lost at 10° C, and the drive 

 for social status continued until the water 

 reached 6° (Noble, 1939). 



9. The female consort of a dominant 

 male tends to be accorded his social status 

 so long as she remains near him (Carpen- 

 ter, 1942). This can be expanded to the 

 more general rule that in closely associated 

 pairs of animals, the social status of both 

 tends to be that won by the more dominant 

 individual. 



10. An ordinarily successful animal may 

 be temporarily tired or ill and so may lose 

 a combat that it might well be expected 

 to win. This is a common cause of triangles 

 of dominance in which a > b > c > a; 

 even the omega individual has been known 

 to dominate the otherwise alpha hen of a 

 flock. 



11. Individuals standing high in their 



own social groups are more hkely to dom- 

 inate a stranger than are those with low 

 social status. Winning, if repeated, tends 

 to produce continued victories in pair con- 

 tests; continued losing predisposes towards 

 further defeats (Ginsburg and Allee, 

 1942). 



12. The paired reactions of animals to 

 each other tend to become fixed with rep- 

 etition, and an old or even an ill individ- 

 ual may continue to dominate vigorous as- 

 sociates long after it has lost the power to 

 defeat them in actual combat. 



13. It is hard enough to judge critically 

 concerning psychological factors in human 

 affairs; the diflficulty is much greater with 

 other animals, but there is much evidence 

 of the importance of such effects in win- 

 ning social status. One animal acts as 

 though intimidated by the appearance of a 

 stranger and gives way without fighting. 

 In other cases, both act as if frightened; 

 the one that recovers first usually wins 

 ( Schjelderup-Ebbe, 1935). Another psy- 

 chological aspect is the appearance in non- 

 human animals of reactions toward flock 

 mates that in man would be regarded as 

 expressing individual antipathy or favorit- 

 ism. Thus high-ranking cocks of the com- 

 mon domestic fowl, when in bisexual 

 flocks, may suppress the mating behavior 

 of some subordinate cocks and allow others 

 even to push them away from the copulat- 

 ing position (Guhl, Collias, and Allee, 

 1945). 



14. Hereditary differences are important, 

 as well as factors related to recent experi- 

 ence; for example, inbred strains of mice 

 may differ both in aggressiveness and in 

 fighting abiUty (Scott, 1942; Ginsburg and 

 Allee, 1942; Beeman, 1947). 



15. Seniority of membership in flocks of 

 similarly aged hens shows a high correla- 

 tion with high social rank (Guhl and Allee, 

 1944). 



The most certain sign of social domi- 

 nance is the winning of an encounter with 

 another individual, either by fighting or by 

 some milder substitute. Often a series of 

 such contacts is needed before the pair 

 relations are definitely established; in some 

 instances, especially between males, the 

 defeated individual repeatedly attacks. 



Defeat is often accompanied by easily 

 observed changes in attitude. A defeated 

 fish may drop its challenging posture of 



