Information we gather from scat includes mammal identification and presence, location of activities, composition of diet, seasonal diet changes, and samples of prey species.

"We are not going to reverse any of the chronic diseases in this country by changing the composition of the diet," Dr. Howard said. "People are always thinking it's what they ate."

Now we'll be able to get a complete picture of what's happening in an infant — from the composition of the diet to the microbes in the gut and the genes that are activated along the way.