Members of a pre-Aztec civilization used human bones—likely from their freshly dead relatives—to make buttons, combs, needles, spatulas, and dozens of other everyday utensils, Mexican archeologists say.

The discovery comes from a new analysis of 5,000 bone fragments found in the ancient city of Teotihuacan, a large archaeological site about 30 miles (48 kilometers) northeast of Mexico City (see map).

Femurs (thigh bones), tibias (shinbones), and human skulls were transformed into household items shortly after death, noted team leader Abigail Meza Peñaloza of the National Autonomous University of Mexico (UNAM).

"The Teotihuacanos used different stones as knives to finely remove the flesh and muscles from the bones," Meza Peñaloza said. The bodies had to be as fresh as possible, she added, because after a person dies, his or her bone quickly becomes too fragile to sculpt.

Rebecca Storey, a Teotihuacan expert at the University of Houston, said that making utensils out of human bone fits with the ancient culture.

"They were not particularly afraid of death," said Storey, who was not involved in the discovery. "They buried the members of their family under and around their houses and manipulated their bones."

"Bone Factory" Used Only Adult Remains

The Teotihuacan metropolis in Mexico, also known as the City of the Gods, is one of the largest ancient urban centers in the Americas. The city thrived between about 100 B.C. and A.D. 650. (See "New Digs Decoding Mexico's 'Pyramids of Fire.'")

The pre-Hispanic culture is known to have practiced human and animal sacrifices, as evidenced by bones buried in the city's temples that are thought to have been offerings to the gods. (See pictures of sacrificial victims unearthed in Teotihuacan.)

The newly analyzed bones were found across a neighborhood of the city called Ventilla. The fragments, which date to the Classic period—the city's heyday, between A.D. 200 and 400—show only marks left by the defleshing process and no signs of ritual sacrifice, the UNAM researchers found.

What's more, the bones used to make the artifacts appear to be from locals, who were traditionally buried under the floors of their family homes.

"When I compared frontal sinuses—a bone so distinctive and unique that it works like a fingerprint—used in the artifacts with those from buried skeletons, they were identical," Meza Peñaloza said.

The bone shapes didn't match samples from skeletons of sacrificed foreigners, indicating that the bone artifacts were made from fellow Teotihuacanos.

The archaeologists also found that artifacts were made only from the bones of adults in their prime, perhaps because childrens' bones were too fragile, while the bones of the elderly might carry diseases such as osteoporosis.

"They preferred the bones of healthy adults who appear to have died of natural causes. But life expectancy at the time was short—people would die in their 30s," Meza Peñaloza said.

Keeping Relatives' Gifts Alive?

For now the UNAM archaeologists don't know who was working at the "bone factory" or what was done with the removed flesh.

And Meza Peñaloza said it's not yet possible to link individual bone artifacts with particular households. But her team does plan to run an isotope analysis to figure out where the people whose bones became utensils likely lived.

By looking at the types of strontium and oxygen atoms found in adult teeth, for example, the researchers can tell where a person drank water, and thus whether they lived most of their lives in Teotihuacan or had moved there from coastal communities.

Meza Peñaloza's team also hopes the find will eventually help archaeologists better understand the symbolism of using bone to make housewares.

"Let's say that an arm bone from someone who was a good tailor was made into a needle to keep the gift alive in a certain way, or that someone used a button from a grandmother to remember her," she said.