Dehydration inhibits suckling behavior in weanling rats.

The relation between dehydration and suckling behavior was determined in weanling rats 14, 20, and 23 days of age. After 15 days of age, intracellular and extracellular dehydration sharply reduced both the number of rats that suckled and the amount of milk consumed. Rehydration returned both behaviors to control levels. Thus, during the weaning period, the internal determinants of suckling are not homologous with those of drinking but are more homologous with those governing feeding.