178 Hormones and the Behavior of Fowl 



ing gull will induce "food-begging," a behavior pattern which is necessary for 

 coition. In mammals BalP" found that estrogen could produce the feminine 

 behavior patterns in castrated male rats, but that these individuals continued 

 to perform the masculine copulatory patterns. That there is some difference 

 in the potentialities of the sexes is shown by the fact that more estrogen is 

 required to produce lordosis in males than in females and that females did 

 not show masculine tendencies under the influence of estrogen. 



The evidence so far accumulated indicates that both sexes of the domestic 

 fowl possess the potentialities for performing certain masculine behavior pat- 

 terns. Crowing, "waltzing," and "tidbitting" occur in males and females under 

 the influence of testosterone. Crowing certainly is induced by androgen, while 

 "waltzing" and "tidbitting," if not actually induced by testosterone, are at least 

 increased in frequency. Further research upon the stimulus situation which 

 will induce a capon to "waltz" is necessary before a solution of this problem can 

 be reached. Fighting and aggressiveness, although occurring in capons, is very 

 greatly increased by the injection of testosterone. That there may be a basic 

 quantitative difference between the sexes is indicated by the observation that 

 capons crowed sooner than poulards under the influence of androgen. 



In contrast to the ability of both sexes to perform certain behavior patterns 

 is the observation that masculine copulatory behavior was not induced by 

 the injection of testosterone into poulards. This is surprising because in some 

 species of birds (Shoemaker;" Noble and Wurm^^) the females are reported 

 to mount, and some poultrymen say that hens sometimes tread one another. 

 Also, there is one case on record (Domm^) in which a sinistrally ovariectomized 

 poulard is known to have performed the male copulatory act. Whether other 

 stimulus situations than those employed in our experiments would elicit copu- 

 lation in a testosterone-injected poulard is not known. In any case, we can 

 confidently state that there is a sexual differential, since under the experi- 

 mental procedures employed the capons copulated whereas the poulards did 

 not. It is of further interest that both androgen and estrogen induced the 

 copulatory behavior pattern in our capons. Apparently in this case the hor- 

 mones are not specific in their action on the nervous system. These results 

 would seem to suggest that the female chicken may not have the proper nerv- 

 ous patterns for the masculine copulatory behavior save in very exceptional 

 cases. 



It is worthy of note that the behavior relative to reproduction may be 

 divided into two types. The primary patterns are related to the actual insemi- 

 nation. The secondary patterns (epigamic, Huxley^) include such actions as 

 singing (crowing) and courtship ("waltzing"). It is perhaps more than coinci- 

 dence that the typical male primary patterns appear to be sex limited but can 

 be activated by either androgen or estrogen, while, on the other hand, the 

 secondary patterns are induced in both sexes by androgen. Further research is 

 necessary to determine the validity and application of this generalization. 



The results of this series of injections throw some light on the problem of 



