Isotopic and genetic analyses of a mass grave in centralCalifornia: Implications for precontact hunter‐gatherer warfare

Abstract

Objectives: 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. Am J Phys Anthropol 159:116-125, 2016. V C 2015 Wiley Periodicals, Inc.A romanticized interpretation often depicts huntergatherers as peaceful peoples with, at most, very low rates of interpersonal violence when compared with more complex and state-level societies. Recent archaeological and anthropological research has challenged these notions (e.g., Walker, 1989;Keeley, 1996;LeBlanc, 1999;Lambert, 2002;Arkush and Allen, 2006; Allen, 2012;Jones and Allen, 2014). These studies suggest that the level of organization in warfare was often lower among hunter-gatherers, but that per-capita rates of non-lethal violence and homicide were often just as high (but see Fry, 2007 andFry andS€ oderberg, 2013 for an alternate perspective).The ancient hunter-gatherers of California have played an important part in this shift in thinking (Walker, 1989;Jurmain, 1991Jurmain, , 2001Jurmain and Bellifemine, 1997;Lambert, 1997Lambert, , 2007Andrushko et al., 2005Andrushko et al., , 2010Jurmain et al., 2009;Bartelink et al., 2013; Eerkens et al., 2014a,b;Schwitalla et al., 2014). Osteological studies show that violence often played a role in mortality. A recent compilation and survey of osteological data (Schwitalla et al., 2014) shows that sharp-force trauma appears in over 7% and blunt-force in over 4% of individuals

Stable isotope evidence of juvenile foraging in prehistoric Central California

“…Additionally, there is evidence of increased rates of interpersonal violence at CA-ALA-554 associated with the MCA, including a mass grave of males exhibiting evidence of perimortem sharp-and bluntforce trauma (Eerkens et al, 2016).…”

Sex estimation using sexually dimorphic amelogenin protein fragments in human enamel

“…Second, archaeological teeth, primarily second and third molars, were collected from individuals with osteological sex estimations. These samples were from open-air contexts in central California and highland Peru, and range in age from 400 to at least 7300 BP (Eerkens et al, 2014;Eerkens et al, 2016a;Eerkens et al, 2016b;Eerkens et al, 2017;Greenwald et al, 2016;Haas et al, 2017;Haas and Viviano Llave, 2015). Third, deciduous teeth completely lacking in contextual sex information were also analyzed.…”

Dental calculus as a source of ancient alkaloids: Detection of nicotine by LC-MS in calculus samples from the Americas

“…CA-ALA-554 is a slightly older archaeological site in the Amador Valley to the east of San Francisco Bay (see Eerkens et al, 2016b). Bone collagen radiocarbon dates from 55 individuals, including one from this study, are consistently between 1800 and 450 cal BP.…”