A new study uncovers far-reaching mobility and enduring traditions along Peru’s Pacific coast.
Long‑distance migration along Peru’s Pacific coast began at least 800 years ago, centuries before the rise of the Inca Empire and well before historians once believed. That’s the striking conclusion of a new international study published in Nature Communications, which combines ancient DNA (aDNA) with archaeological and historical evidence to paint a vivid picture of pre‑Inca mobility.
The findings challenge long‑held assumptions that coastal communities were relatively static before Inca rule (AD 1400–1532). Instead, the study reveals that people traveled more than 700 kilometers from Peru’s north coast to the Chincha Valley in the south, where they settled, intermarried, and yet preserved distinctive cultural traditions for generations.
Among the most evocative discoveries: a single grave containing relatives who practiced endogamy, or close‑kin procreation, underscoring the importance of kinship ties in ancient Andean society.
“Migration and kinship have long been part of the human story and the development of powerful societies,” said co‑lead author Dr. Jacob Bongers, digital archaeologist and member of the Vere Gordon Childe Center at the University of Sydney, and Visiting Research Fellow at the Australian Museum Research Institute.
“What’s most interesting about this research is that it shows the close‑knit and far‑reaching social networks of pre‑Inca coastal communities, as well as how people maintained cultural traditions of marking group identities for centuries, even as they intermarried with distinct groups,” he added.
The team analyzed aDNA samples from 21 individuals recovered from burial sites in the Chincha Valley, reconstructing family relationships and genetic diversity across centuries.
“The genome‑wide data and radiocarbon dates suggest migrants arrived in the Chincha Valley by at least the thirteenth century AD, well before Inca expansion,” Dr. Bongers explained. “Their ancestry traced back to the Peruvian north coast, more than 700 kilometers away, and the aDNA of these early migrants revealed no evidence of mixing with local populations.”
Over time, however, genetic evidence showed mixed ancestry between people from the north, central, and south coasts. “This likely means that, after northerners migrated to Chincha, they intermarried with groups from neighboring coastal areas, a practice that continued during the Spanish Colonial Period (AD 1532–1825),” Dr. Bongers said.
Genetic and bioarchaeological data also revealed close‑kin procreation.
“The burial of family members together and the evidence for close‑kin unions in the lower Chincha Valley highlights the importance of the familial unit for ancient Andeans,” said co‑lead author Assistant Professor Jordan Dalton from the State University of New York, Oswego.
“The close biological relationships suggest the sampled individuals were members of an ayllu or parcialidad, a traditional, kin‑based group that shares common territory, resources, and ancestry. Close‑kin unions may have served as a strategic means of retaining control over resources within the group,” she explained.
All sampled individuals had some north coast ancestry, showing population continuity for at least 200 years. This recurrent genetic signature tracked the stable and long-term cultural continuity in the Chincha region from the thirteenth to the fifteenth centuries.
“In the sampled individuals from the lower and middle valley, we observed practices such as cranial modification, a process carried out in infancy to shape the head using boards and bindings, human vertebrae strung on reed sticks, and the postmortem application of red pigment to the skull,” Dr. Bongers said.
“Postmortem red pigment application and cranial modification are cultural traditions that have long been documented on Peru’s north coast, so this evidence shows migrants may have brought their body modification traditions south to mark group identities.”
Why did they move?
The timing of migration from northern Peru aligned with major social and political changes along the coast, though the precise reasons remain uncertain.
“Climate hazards, the expansion of powerful northern polities such as the Chimú, and access to valuable resources including seabird guano, are all possible drivers of ancient Andean migration,” Dr. Bongers said.
He added: “Importantly, this research expands our understanding of how and when interregional interaction occurred along the Andean Pacific coast and makes it clear the Inca incorporated highly mobile and deeply connected coastal communities into their empire.”
Overall, the combined results reshape our view of pre‑Inca coastal societies as dynamic, mobile communities linked by dense kinship networks and deep traditions, rather than functional groups living in isolated villages. The behavior of their migrations, strategic marriages, and their complex rituals all contributed to the multifaceted social system that existed centuries before the mighty Inca Empire rose to power.
Further, an imprint of their social structure, traditions, and solidarity persisted into the colonial period, creating a legacy that continued to resonate well beyond their polity and across generations and historical periods.
Through the integration of DNA analysis, archaeological findings, and historical records to carefully delineate these old and complex journeys, paleogenologists have cast light on a neglected area in Peru’s complex past, one where migration was not simply an occurrence or anomaly but rather one of the defining aspects of everyday living for those who resided along this long and diverse Pacific coastline.
