Archaeologists in Mexico City have made an extraordinary discovery—the skeletons of 12 dogs all mysteriously buried together more than 500 years ago, in the Aztec capital of Tenochtitlan.

Dog burials have been uncovered before at archaeological digs, but this is a first such finding not associated with a building or a human burial, according to a report published in Spanish last week by Mexico's National Institute of Anthropology and History (INAH).

Dogs were important symbolically in Aztec mythology. They were believed to serve their masters even after death, guiding the soul of the deceased through the many hazardous layers of the underworld to reach Mictlan, the place of the dead. Also, a god known as Xolotl—sometimes depicted with the head of a dog—had strong ties to the underworld.

Whether the Aztecs associated the buried dogs with such symbolism is still unknown. The researchers hope that the burial offers deeper insights into how dogs were regarded by the residents of the chief city of the Aztecs.

Pet Cemetery

Working in an area measuring 6.5 square feet (two square meters), the archaeologists discovered the canine remains between 4.2 feet (1.3 meters) and 5.5 feet (1.7 meters) below the current street level.

The skeletons were mostly complete and well preserved, but their burial follows no particular pattern that the archaeologists could discern.

View Images Whether the Aztecs associated the buried dogs with mythological symbolism is still unknown. Photograph by Melitón Tapia, INAH

The dogs were all of medium height, represent various ages at death, and retained most of their teeth. They were probably common dogs, not native Mexican breeds such as the techichi (known for their short stature) or the xoloitzcuintli (which loses its premolar teeth in adulthood).

Nearby excavation sites yielded a style of pottery known as Aztec III. These orange-clay vessels, decorated in black geometric designs, help date the dogs to the period known as the Late Postclassic, from A.D. 1350 to 1520.

Dog Dinners

The archaeological investigations have been carried out in the neighborhood known as Azcapotzalco, in the northwestern part of the sprawling Mexican capital. During ancient times, this area would have sat on the western shore of the lake known as Texcoco, which is now a dry lakebed completely covered with the city's buildings and streets.

Archaeologists believe that the Aztecs who lived in this neighborhood may have deposited their domestic trash along the lakeshore in order to raise the level of the land and prevent flooding. A variety of domestic artifacts have come to light in the area, such as pottery, bone needles, obsidian blades, musical instruments made from human and canine bones, the carved bone of a deer, and the bones of turkeys and dogs that were served as meals.

Yes, the Aztecs ate dogs. In fact, they raised the animals mostly for food.