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ABSTRACT: Stable carbon and nitrogen isotope analyses of bones and teeth at the ancestral heritage Muwekma Ohlone site of Yakmuy ́Ooyákma-tka (“Place of the East Ridge Site”; CA-SCL-215) reveal significant differences in the dietary life history of males and females. Overall, isotope data indicate that site inhabitants were primarily dependent on low-trophic-level foods, likely plants, and minor amounts of marine food for their main source of dietary protein. From tooth dentin serial samples, we found that males and females were similar for δ13C in early childhood (age 1–9 years), but boys were elevated in δ15N by 0.6–1.0‰ relative to girls, indicating boys were accessing slightly greater amounts of higher-trophic-level foods, such as meat from game. The sex-biased difference in δ15N diminishes during the second decade of life, as female δ15N values increase and become equal to males. However, a difference in δ13C emerges during the second decade: female δ13C values are elevated relative to males. This could indicate that teenage females consumed higher amounts of low-trophic-level, marine-derived protein, such as shellfish. During later adult years the difference in δ13C disappears, while males again show an increase in δ15N relative to females. Although these differences are small, they reveal important sex-biased life history patterns during childhood and adulthood in this ancient community. 

This article reports new carbon, nitrogen, and sulfur isotope data for 10 individuals on the San Francisco Peninsula from CA-SMA-78 (Hamilton Mound 20; n = 6), CA-SMA-160 (Hiller Mound; n = 3), and a previously unrecorded site in downtown San Mateo (n = 1). We also report seven new bone collagen accelerator mass spectrometry radiocarbon dates, three from CA-SMA-78 that fall during the Early-Middle Transition and early Middle Period (ca. 2,400 and 1,700 cal BP), three from CA-SMA-160 that fall during the late Middle and Middle-Late Transition periods (ca. 1,080 and 770 cal BP), and one from the unrecorded site that falls during the Late Middle Period (ca. 1,260 cal BP). Dietary isotopes show a bimodal pattern, with most individuals (n = 8) consuming a mixed marine-terrestrial diet and two a terrestrial-dominant diet (n = 2). We propose two hypotheses to explain this variation, the first suggesting independent family-level hunting and gathering territories combined with little intra-group sharing of food, and the second suggesting exogamous marriage patterns with people migrating from regions to the south. Future isotopic research could provide support for one (or both) of these hypotheses. 

This article reports new carbon, nitrogen, and sulfur isotope data for 10 individuals on the San Francisco Peninsula from CA-SMA-78 (Hamilton Mound 20; n = 6), CA-SMA-160 (Hiller Mound; n = 3), and a previously unrecorded site in downtown San Mateo (n = 1). We also report seven new bone collagen accelerator mass spectrometry radiocarbon dates, three from CA-SMA-78 that fall during the Early-Middle Transition and early Middle Period (ca. 2,400 and 1,700 cal BP), three from CA-SMA-160 that fall during the late Middle and Middle-Late Transition periods (ca. 1,080 and 770 cal BP), and one from the unrecorded site that falls during the Late Middle Period (ca. 1,260 cal BP). Dietary isotopes show a bimodal pattern, with most individuals (n = 8) consuming a mixed marine-terrestrial diet and two a terrestrial-dominant diet (n = 2). We propose two hypotheses to explain this variation, the first suggesting independent family-level hunting and gathering territories combined with little intra-group sharing of food, and the second suggesting exogamous marriage patterns with people migrating from regions to the south. Future isotopic research could provide support for one (or both) of these hypotheses. 

The earliest Native Americans have often been portrayed as either megafaunal specialists or generalist foragers, but this debate cannot be resolved by studying the faunal record alone. Stable isotope analysis directly reveals the foods consumed by individuals. We present multi-tissue isotope analyses of two Ancient Beringian infants from the Upward Sun River site (USR), Alaska (~11,500 years ago). Models of fetal bone turnover combined with seasonally-sensitive taxa show that the carbon and nitrogen isotope composition of USR infant bone collagen reflects maternal diets over the summer. Using comparative faunal isotope data, we demonstrate that although terrestrial sources dominated maternal diets, salmon was also important, supported by carbon isotope analysis of essential amino acids and bone bioapatite. Tooth enamel samples indicate increased salmon use between spring and summer. Our results do not support either strictly megafaunal specialists or generalized foragers but indicate that Ancient Beringian diets were complex and seasonally structured.