1182 



HORMONAL REGULATION 



up to and including various degrees of 

 mounting (Stone, 1927, 1932a; Beach, 1944b; 

 Beacli and Holz, 1946; Grunt and Young, 

 1953 ) , but as the decrease in the score in one 

 experiment indicates, the change is great, 

 from an average of 7.8 in 290 tests before 

 castration to an average of 2.0 in the tests 

 of 29 animals 14 weeks after castration 

 (Grunt and Young, 1952b). 



Preliminary observations suggested that 

 male dogs exhibit the full capacity for coitus 

 and orgasm several months after castration 

 (Beach, 1947-48). Subsequently (Beach, 

 1952), this extreme view was modified in a 

 statement that the average sexual perfor- 

 mance declines progressively after removal 

 of the testes. Nevertheless, a real difference 

 exists between the reaction of dogs and ro- 

 dents to castration. Beach writes: "... 

 nearly all animals retain some ability to 

 penetrate the receptive bitch even two years 

 after the operation. Furthermore, there are 

 at least a few individuals in which there oc- 

 curs no detectable loss of sexual responsive- 

 ness or ability to copulate. In point of fact 

 some dogs are more vigorous and potent two 

 years after castration than they were pre- 

 operatively." 



The behavior of the boar is said to be 

 "greatly altered" by castration (Wallace, 

 1949), but the descriptive account elsewhere 

 in the article suggests that many elements 

 of the mating behavior pattern are retained: 



"One week after the operation there was 

 a striking change in the animal's behaviour; 

 from being excitable and one of the most 

 ferocious of the boars, he was now sluggish, 

 rather plaintive and exceedingly unwilling 

 even to approach the dummy sow. After 

 several attempts at the first trial he was 

 forcibly driven and held right up to the 

 dummy, when he mounted and mating re- 

 actions followed normally. In the next few 

 weeks he fell again into the routine of col- 

 lections, and though reluctant would always 

 mount." 



Parenthetically we would note that the in- 

 terval necessary to drop the copulatory 

 drive of the rabbit below the effective mini- 

 mum for copulation varies directly with the 

 strength of drive at the time of castration 

 (Stone, 1932a) , and that castration depresses 

 mating tendencies of the rat and hamster 



least in tlie most vigorous copulators and 

 most in the less active individuals (Beach, 

 1948; Beach and Pauker, 1949). Experience 

 with the guinea pig has been different. The 

 capacity for ejaculation is lost earlier by 

 low score males, but when the average pre- 

 castrational score was taken as 100 per cent 

 and the subseciuent change as the percentage 

 of variation from this level, the scores of 

 the high, medium, and low score animals de- 

 creased at the same rate and to approxi- 

 mately the same base-line (Grunt and 

 Young, 1953). 



While discussing the effect of castration 

 on the behavior of the rat and guinea pig, we 

 would direct attention to data collected by 

 Beach (1942d) and Grunt (1954). Beach de- 

 scribed the intense excitement of prepuber- 

 tally castrated and presumably sexually in- 

 experienced male rats when confronted with 

 a receptive female: 



"They dashed wildly about the testing 

 cage, often running in close circles around 

 the female. Vigorous digging in the sawdust 

 covering the cage floor was common. Some 

 males lay on one side and moved all four 

 legs in rapid running movements. Most 

 of the males pursued the female, crowding 

 her roughly against the cage walls, jumping 

 over her and often landing directly upon her 

 back. . . . The amount, intensity and dura- 

 tion of the sort of behavior described above 

 appeared to be inversely related to the vigor 

 and frec]uency of masculine copulatory re- 

 sponses." 



Grunt has noted what may be a corres- 

 ponding behavior during tests of castrated, 

 sexually experienced male guinea pigs. The 

 behavior, nondirected hyperexcitability , — 

 not to be confused with the "state of agita- 

 tion" described by Craig (1918) and Dell 

 (1958) — is characterized liy a sudden 

 straightening of the limbs, a jumping into 

 the air, and frequently by a turning of the 

 head. These actions occur suddenly and do 

 not fit into any sequence of behavior usu- 

 ally seen. The excited movements seem to 

 occur without reference to the female or to 

 the other behavior exhibited during the test. 

 The amount of the behavior increased as 

 overt sexual behavior decreased. When such 

 castrates were given 25 ju,g. or more testos- 

 terone propionate per 100 gm. body weight 



