Maternal influences on ontogeny of suckling and feeding rhythms in the rat.

To assess the effects of both maternal and endogenous factors on the ontogeny of nocturnal feeding in the rat, day and night weight gain was determined in the sighted or blind litters of sighted or blind litters of sighted or blind dams and in young weaned at 15 days of age. Sighted dams impose a diurnal milk-intake pattern on their young. The nocturnal pattern of solid-food intake begins at 19 days of age. Blind litters also display nocturnal feeding when kept with sighted dams, but only until 35 days of age.