The mother-litter relationship in developmental rat studies: cannibalism vs caring.

This incidence of cannibalism was studied in a series of developmental studies (on neonatal lesions, prenatal stress, prenatal surgery, unoperated controls) in which rats were manipulated during either the prenatal or early postnatal periods. Cannibalism during the preweaning period occurred in from 0 to 33% of the litters, depending on the treatment group. It was found in most cases, however, that mothers who cannibalized were also good caretakers of their remaining pups. The same litters were also involved in preweaning tests of mother-young interactions to determine if experimental treatments altered the maternal-filial relationship. It was found that as early as postnatal Day 4, nursing episodes were predominantly pup-initiated in the lesioned litters but mother-initiated in control litters.