[The analysis of maternal behavior in tame and aggressive rats]

Maternal behavior in rodents is associated with long-term programming of individual coping capacities in the offspring and includes a large number of components. This work was aimed to study maternal behavior in tame and aggressive gray rats selected for absence and enhancement of aggressiveness towards human. The study was carried out from 1 to 12 days of nursing at various time of day. It was shown that the frequency of "outside the nest" and passive nursing was higher and the frequency of maternal arched-back nursing and mother licking/grooming was lower in tame compared to aggressive dams especially at the first week of nursing. The tame dams spent less time building nest, they displayed "rest" and self-grooming more frequently. Beginning from the first week of nursing the frequency of "outside the nest" increased in the morning (09:00) and the evening and night (18:00 and 22:00) in tame dams, while the increase of activity was observed in aggressive females only in dark phase (22:00). In the third week of nursing the similar circadian changes of activity were observed in tame and aggressive dams. It is supposed that decreased anxiety in tame compared to aggressive dams could provoke the attenuation of maternal behavior.