Locomotor activity and social behavior of old rats after preweaning undernutrition.

Rat pups were undernourished from birth to 25 days of age by giving them a nipple-ligated mother and a normal lactating mother for alternate periods of 12 hr/day, thus providing adequate full-time maternal care. Male and female rats undernourished neonatally had greater locomotor activity than controls in old age (16-20 months)mfemales were more activive than males, irrespective of neonatal undernutrition. At the age of 24 months, social behavior was recorded at various times of the day for pairs of male rats (1 previously undernourished and 1 control). With one minor exception, undernourished animals did not differ significantly from controls in the incidence of the various behavioral items that were scored. Neonatal social factors may compensate for possible negative effects of neonatal undernutrition on later social behavior.