On the edge of Mexico City's famed Zócalo plaza, next to the ruins of the Aztec sacred pyramid known as the Templo Mayor, the remains of an animal—perhaps a dog or a wolf—were discovered.

This was an essential precaution, as weaning would not take place until the child was two years or older, and the Aztec had no animals whose milk could be used as a substitute. During those four ...

The remains of nearly 200 animals found in Mexico's Teotihuacán are helping reconstruct history. The unearthing and significance of these remains, found in four chambers within the Moon Pyramid—dating ...