Isotopic and genetic analyses of a mass grave in central California: Implications for precontact hunter-gatherer warfare.
OBJECTIVE
Analysis of a mass burial of seven males at CA-ALA-554, a prehistoric site in the Amador Valley, CA, was undertaken to determine if the individuals were "locals" or "non-locals," and how they were genetically related to one another.


METHODS
The study includes osteological, genetic (mtDNA), and stable (C, N, O, S) and radiogenic (Sr) isotope analyses of bone and tooth (first and third molars) samples.


RESULTS
Isotopes in first molars, third molars, and bone show they spent the majority of their lives living together. They are not locals to the Amador Valley, but were recently living to the east in the San Joaquin Valley, suggesting intergroup warfare as the cause of death. The men were not maternally related, but represent at least four different matrilines. The men also changed residence as a group between age 16 and adult years.


CONCLUSIONS
Isotope data suggest intergroup warfare accounts for the mass burial. Genetic data suggest the raiding party included sets of unrelated men, perhaps from different households. Generalizing from this case and others like it, we hypothesize that competition over territory was a major factor behind ancient warfare in Central California. We present a testable model of demographic expansion, wherein villages in high-population-density areas frequently fissioned, with groups of individuals moving to lower-population-density areas to establish new villages. This model is consistent with previous models of linguistic expansion.
Department of Anthropology, University of California, Davis, CA.
Jelmer W
JW
Eerkens
Department of Forensics, University of California, Davis, CA.
Traci
T
Carlson
Department of Anthropology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL.
Ripan S
RS
Malhi
William Self Associates, Orinda, CA.
Jennifer
J
Blake
Department of Anthropology, California State University, Chico, CA.
Eric J
EJ
Bartelink
Department of Geoscience, Aarhus University.
Gry H
GH
Barfod
William Self Associates, Orinda, CA.
Alan
A
Estes
Trina Marine Ruano Family, Union City, CA.
Ramona
R
Garibay
Department of Spectrometry, Interdisciplinary Center for Plasma Mass, University of California, Davis, CA.
Justin
J
Glessner
Department of Anthropology, University of California, Davis, CA.
Alexandra M
AM
Greenwald
William Self Associates, Orinda, CA.
Kari
K
Lentz
Department of Anthropology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL.
Hongjie
H
Li
Department of Anthropology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, IL.
Charla K
CK
Marshall
D000293:Adolescent; D000328:Adult; D000885:Anthropology, Physical; D001842:Bone and Bones / Q000737:chemistry*; D002048:Burial / Q000266:history*; D002140:California; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000235:genetics; D049690:History, Ancient; D006801:Humans; D007554:Isotopes / Q000032:analysis; D008297:Male; D014070:Tooth / Q000737:chemistry*; D014754:Violence / Q000266:history*; D014857:Warfare; D055815:Young Adult
D004272:DNA, Mitochondrial; D007554:Isotopes
C N O Sr isotopes; California prehistory; ancient mtDNA; human provenancing; hunter-gatherer violence