Ceramic baby bottles first started appearing in Europe about 7,000 years ago, as societies shifted from hunting and gathering to settled agricultural communities in the beginning of the Neolithic period. With narrow spouts and playful shapes that sometimes resemble animals, these diminutive vessels are easy to imagine in the hands of infants. But what were children drinking from them?

According to a new study in the journal Nature today, at least some communities in southern Germany were feeding their babies animal milk—perhaps as part of the weaning process—at least 3,000 years ago.

Weaning from a diet of human milk is not only a critical milestone in the early life of an individual, but the practice, on a population