The paper explores the influence of littling sex and age, as well as mother’s body weight, size and sex composition of breed onto the ontogenesis of social behavior of water vole Arvicola amphibius L. The authors conducted experiments and explored the relation among the littlings of each breed in two key periods of postnatal ontogenesis. The authors explored behavior ontogenesis of 88 water voles’ littlings in 19 breeds. The behavior was recorded conducting the tests by means of placing the littlings on a neutral arena; first time it was conducted when the littlings aged 10 days and then at the age of 20 days. The researchers evaluated motor activity and elements of peaceful and aggressive behavior. The results showed that females more often demonstrate peaceful forms of social behavior than males. Negative relationship between frequency of peaceful contacts among the littlings on the mother’s body weight after birth and the proportion of males in the breed. When water voles age 20 days, the frequency of peaceful contacts among the littlings decreases, and the frequency of aggressive contacts increases. Inter-sex differences in the frequency of aggressive contacts have not been detected. The authors found out that aggressive contacts among sibs are initiated by females. The frequency of theses contacts relates to the number of breeds in which they were born and grew up, while the aggressiveness of males does not depend on the amount of their breeds.
EXPERIMENTAL INVESTIGATION OF SOCIAL BEHAVIOR ONTOGENESIS OF ARVICOLA AMPHIBIUS L. IN THE EARLY POSTNATAL PERIOD
