As long as 7,000 years ago, Stone Age farmers in Central Europe were making and using small pottery bottles or cups with spouts. Ancient baby bottles?

So it seemed — although they could have been used to nurse the sick. As the Stone Age gave way to the Bronze and Iron ages, the vessels were more widely used, and some took on the shapes of animals. Archaeologists have found the small containers in the graves of children and infants, suggesting they were used in weaning children from breastfeeding.

But until now, researchers had not analyzed residues in the containers. On Wednesday archaeologists reported in the journal Nature that three such objects, all found in the graves of children in Bavaria dating from about 2,500 to 3,200 years ago, once held dairy products, most likely milk from ruminants, like cows or goats.

Proving exactly how any ancient bit of pottery was used is difficult. But Julie Dunne, a geochemist at the University of Bristol in England and one of the authors of the report, said the location of the feeding cups in child graves along with the new chemical evidence is “as close as you’re going to get” to that proof.