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Introduction
Page 1
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Experiment 1:
Intro/Method
Pages 2-3
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Experiment 1:
Results
Page 4
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Experiment 1:
Discussion
Page 5
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Experiment 2:
Intro/Method
Page 6
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Experiment 2:
Results
Page 7
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Experiment 2:
Discussion
Page 8
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Experiment 3:
Intro/Methods
Page 9
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Experiment 3:
Results
Page 10
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Experiment 3:
Discussion
Page 11
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General Discussion
Page 12
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Figures 1-2-3
Pages 13-14-15
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Tables 1-2-3
Pages 16-17-18
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These data are consistent with previous studies of competitive fighting. The scores of normal males against normal male opponents and normal females against normal female opponents were quite similar to those found by Mink and Adams (13) in their control group (nonhandled, tested in home cage). And like those results, the females fought about twice as much as the males. This consistency of results was to be expected because both experiments used the homozygous DA rats which have no genetic variance. the results differed, however, from those of Zook and Adams (15) who found an equal amount of fighting by male and female DA rats.
The data are consistent with the findings of Albert et al. (6, 7) who found decreases in competitive fighting after castration of males and ovariectomy of females.
Unlike the findings of previous investigators for territorial fighting, males were not more likely to fight against opponents of the same sex, and while there was a tendency for females to attack other females more than males, it was not as great as one normally sees in territorial fighting.
Other aspects of the data are also different from territorial fighting. In territorial fighting, castration usually increases the fighting of males against a female opponent, whereas the opposite was obtained. Also, from territorial fighting, one would predict that the overall rates of attack would be higher for males than for females, which was the opposite of what was obtained.
If we assume that competitive fighting is organized in a different way than territorial fighting, we are free to consider other interpretations of the data.
The greater fighting against female Fischer opponents could have been due to their smaller size than male opponents. Whereas the opponent Fischer males weighed an average of 281 g. the opponent Fischer females weighed only an average of 186 g. DA males and females weighed 290 and 205 g on average, respectively. The effect of offense could have been mediated by fear, with less fear against the smaller female opponents.
Fear was probably a factor. We found higher rates of upright posture against male opponents. Upright posture is an ambivalent posture in the sense that it is seen not only in offense, but in defense and submission as well (3). Fear has been shown to inhibit offense (13).
The greater fighting against female opponents was unaffected by gonadectomy, which suggests that it is not based on hormonal factors. Although the overall amount of fighting was decreased by gonadectomy, the proportion of attacks against male and female opponents remained similar as may be seen in Fig. 1.
Gonadectomy did reduce the overall levels of fighting and reduced the degree to which females fought more than males, which suggests that there may be hormonal effects directly upon the synthesizer for competitive fighting. One may hypothesize from these data that estrogens have a greater effect than androgens, and that the effect is both organizational around the time of birth and activational at the time of testing. The latter is suggested by the finding that the differential between female and male fighting is reduced but not totally abolished by gonadectomy. This hypothesis needs to be tested by another type of study involving perinatal as well as adult gonadectomies.
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