In "Gulp: Adventures on the Alimentary Canal," Mary Roach explores various aspects of human digestion, including an intriguing observation about drooling in newborns. She explains that the absence of teeth plays a significant role in this phenomenon, as teeth typically help retain saliva within the mouth. Without teeth to hold the saliva in place, infants naturally produce and release more drool.

Roach delves into the mechanics behind this process, shedding light on the biology of infants and their unique physiological traits. This insight not only satisfies curiosity about a common occurrence in babies but also illustrates the fascinating intricacies of the alimentary canal and human development.