Ties that Bind

A plaster cast of an elongated skull.

Dan Chamberlain, Cornell University

As a highly social species, humans use language, clothing, rituals, body adornment, and body modifications—among other practices—as markers to establish group identity. About a millennium ago, an ethnic group in the Andes mountains used head binding to modify their infants’ malleable skulls. A new study has examined how this head shaping may have engendered social differences and conferred benefits on those individuals with the artificial alteration.

Matthew Velasco, assistant professor of anthropology at Cornell University, studied aboveground burial sites in the Colca Valley in what is now Peru. These tombs contained, primarily, the remains of high-status individuals from the Collagua ethnic group. Through radiocarbon dating of bone samples and examination of well-preserved skulls, Velasco determined that a long and narrow skull shape favored by the Collaguas grew more common over the Late Intermediate Period (LIP) from 1150 to 1300 ce. In the first half of the LIP, about 39 percent of skulls exhibited modification, with modified skull shapes roughly evenly distributed between elongation and a squat and wide skull compression favored by the neighboring Cavanas ethnic group. By the second half of the LIP, however, the proportion of modified skulls jumped to almost 74 percent, with most modified skulls exhibiting elongation.

According to Velasco, the symbol of an elongated head could have promoted cohesion within Collagua communities, as “head shape would be an obvious signifier of affiliation and could have encouraged unity among elites and increased cooperation in politics.” Increasing this display of unity could have helped during the LIP, a period marked by conflict caused by the collapse of the Wari and Tiwanaku empires on the Peruvian coast, coupled with the expansion of the Incan empire.

Aboveground tombs at the cemetery site of Yuraq Qaqa in the Colca Valley of Peru.

David Rodríguez Sotomayor, Proyecto Bioarqueológico Coporaque

Cranial modification as a status, or cultural, symbol may also have contributed to growing social inequality in the tumultuous era. Velasco will return to Peru this summer to investigate whether skull shape conferred societal privileges, such as better feeding during childhood or less risk of being subjected to violence. Bones can tell such tales through porous lesions that occur when marrow expands due to anemia or malnutrition, or through evidence of prior fractures. (Current Anthropology)