Late Holocene Paleodietary Patterns Among the Ancestral Ohlone: Ecogeographic Partitioning of Resources Along the San Francisco Bay Eastern Shore

Objectives

In the San Francisco Bay Area, Late Holocene resource intensification models predict an increase in diet breadth and a reduction in foraging efficiency associated with an increase in population, sedentism, and territoriality among fisher-hunter-gatherer populations. Here we compare bone stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values of sites along the eastern bay shore to interpret how ecogeographical partitioning of resources by latitude and distance from the bay reflects differential access and control of resources.

Materials and Methods

With the support of, and in collaboration with, the Muwekma Ohlone Tribe of the San Francisco Bay Area, we analyzed bone collagen and bioapatite from 154 burials from Mánni Muwékma Kúksú Hóowok Yatiš Túnnešte-tka (CA-ALA-329) (2500–180 cal B.P.) to examine temporal changes in diet. Further, we examined the ecogeographical partitioning of resources in relation to published data from four contemporaneous sites.

Results

For collagen (n = 146), δ¹³C values average −18.2‰±0.7‰ (1SD) and δ¹⁵N values average 9.8‰±1.5‰ (1SD). For bioapatite (n = 144), δ¹³C values average −13.8‰±1.0‰ (1SD). Adult males had statistically significantly higher isotope values compared to adult females, but differences were minimal (< 1.1‰). No meaningful temporal changes in diet were identified. Regional dietary differences occurred along a latitudinal gradient of the eastern bay shore.

Discussion

Foraging efficiency was localized, suggesting that the exploitation of different microhabitats was critical to each tribal group. Stable isotope data complement zooarchaeological and paleobotanical data; although they reveal different aspects of subsistence practices and diet.