Gulp: Adventures on the Alimentary Canal

by Mary Roach

As babies, we learn to talk by naming what we see. “Baby points to a lamp, mother says, ‘Yes, a lamp,’” says Johan Lundström, a biological psychologist with the Monell Chemical Senses Center in Philadelphia. “Baby smells an odor, mother says nothing.”

(Intestinal taste receptors are thought to trigger hormonal responses to molecules, such as salt and sugar, and defensive reactions—vomiting, diarrhea—to dangerous bitter items.)

Snakes are keenly attuned to the aroma of favored prey—so much so that if you slip a rat’s face and hide, Hannibal Lecter–style, over the snout of a non-favored prey item, a python will try to swallow it. (University of Alabama snake digestion expert Stephen Secor did this some years back to reenact a scene for National Geographic television. “Worked like a charm,” he told me. “I can get a python to eat a beer bottle if I put a rat head on it.”)