HORMONES AND MATING BEHAVIOR 



1181 



ual behavior was displayed by two turkeys, 

 castrated at 9 weeks of age (Scott and 

 Payne, 1934). Sexual behavior is "wanting" 

 in castrated ducks and roosters (Goodale, 

 1913, 1916b) , but elsewhere (Goodale, 1916a, 

 1918) it is evident that capons frecjuently 

 crow and sometimes tread hens, although or- 

 dinarily these phases of the behavior of the 

 cock are not manifested. Benoit (1929) 

 stated that the capon normally shows no 

 interest in hens, but one in which no testicu- 

 lar tissue could be found and which pos- 

 sessed a comb and wattles typical of the 

 capon did tread hens. Domm (1927) referred 

 to capons in his pens which crowed and trod 

 hens, but when such individuals were exam- 

 ined small nodules of testicular tissue were 

 found. 



^^'llen articles dealing with mating behav- 

 ior in castrated lower mammals are re- 

 viewed, the conclusions must be evaluated 

 carefully. The significance of the statement 

 that male guinea pigs castrated at 30 days 

 of age have repeatedly been utilized as 

 testers for estrous females (Moore, 1928; 

 Moore and Gallagher, 1930) is lessened by 

 the statement (Moore and Gallagher, 1930) 

 that "such animals usually do not carry on 

 copulation, but their pursuing instincts are 

 still strong." 



Display of the normal strength of copula- 

 tion by the rat 4 months, 6 months, and 1 

 year after castration (Steinach, 1894) has 

 not since been reported. To be sure, copula- 

 tory activity as long as 8 months after cas- 

 tration was recorded by Stone (1927), but 

 "copulatory" denoted the overt elements of 

 the copulatory response without indication 

 as to insemination or intromission. In a later 

 report (Stone, 1939a) the last ejaculation 

 was seen 30 days after castration and the 

 mean number of copulations at this time was 

 21.8 in 5 controls and 3.6 in 10 experimental 

 animals. 



The normally developed penis in the male 

 guinea pig which retained its sexual ardor 

 6 months after castration (Guimarais. 1928) 

 suggests there was androgenic stimulation. 

 In a more recent study no such persistence 

 of mating behavior was evident in any of 60 

 castrated males (Grunt and Young, 1953). 

 Seward's (1940) statement that a prepuber- 

 ally castrated guinea pig went through the 



entire copulatory pattern ai)proximately a 

 month after castration is not believed to 

 constitute evidence for the postcastrational 

 display of a strong sex drive. It is clear from 

 the scale of sexual agressiveness he used and 

 from what we now know about the sexual 

 behavior of this species that intromission 

 was not always distinguished and that ejac- 

 ulation was not identified. 



To the casual reader there is an ambig- 

 uity in the use of the word copulation which 

 may have influenced our concepts of the 

 effects of castration on lower mammals. In- 

 tromissions preceding ejaculation, and in- 

 tromissions accompanied by ejaculation are 

 a part of the complete masculine response, 

 but in much of the work on the effects of 

 castration, ejaculation was not the end point. 

 In the articles on the rat before 1934, copu- 

 lation was used without implication as to 

 insemination (Stone, 1927) or even intromis- 

 sion in the case of castrated males. "Com- 

 plete copulation" in the contemporary lit- 

 erature on the mating behavior of the rat 

 does not include ejaculation. Mounting was 

 an end point in a study of castration and 

 replacement therapy in which the guinea 

 pig was used (Sollenberger and Hamilton, 

 1939) , but reference was made to copulatory 

 Ijehavior. For the careful reader, this use of 

 copulation is not confusing, but for the hasty 

 reader the effects of castration could easily 

 be minimized, because the lower elements of 

 the mating behavior pattern are influenced 

 less by castration than are intromission and 

 ejaculation (Stone, 1923, 1932a; Beach, 

 1944b; Beach and Pauker, 1949; Grunt and 

 Young, 1953; Riss, Valenstein, Sinks and 

 Young, 1955). 



If allowance is made for the considerations 

 discussed above, the investigations reported 

 during the last 30 years are believed to lead 

 to the conclusion that a gradual and con- 

 spicuous decrease in mating behavior fol- 

 lows the castration of such laboratory mam- 

 mals as the rat, guinea pig, rabbit, hamster, 

 and cat (Stone, 1923, 1927, 1932a, 1939a; 

 Nissen, 1929; Beach, 1942d, 1944b; Beach 

 and Holz, 1946; Beach and Pauker, 1949; 

 Grunt and Young, 1952b, 1953; Green, Cle- 

 mente and de Groot, 1957; Rosenblatt and 

 Aronson, 1958a). The pattern of behavior 

 still contains some of the mating reactions 



