| Abstract: | Male and female bank voles reared in different conditions were investigated for their aggressiveness in order to show how social factors modify intermale and interfemale behavior. Singly reared males or females were paired with a tested animal for 10 min. The number of attacks and the accumulative attack times of singly reared males were higher than for females reared in similar conditions. The differences were not, however, statistically significant due to the variation among tested animals. There were significant differences in aggressiveness of females reared in various conditions before the test. Most attacks were observed in females reared with intact males. In this group, the accumulative attack time was significantly higher than that of singly reared, grouped females, or females kept with castrated or castrated-testosterone-treated males. Also, the aggression of males was affected by breeding. Both the number of attacks and the accumulative attack times were elevated in intact males kept with females. Housing of males in groups and castration significantly decreased the number of attacks of these animals. Injection of testosterone increased aggression in castrated males. It is suggested that olfactory signals in bank voles released by males increase aggression in females and the female's signals stimulate male behavior. |
