A simple carbon isotope model for reconstructing prehistoric human diet

Area of Science:

• Paleoecology
• Isotope Geochemistry
• Archaeological Science

Background:

• Traditional isotopic analyses (delta13C in collagen, apatite, and CO-AP) are insufficient for reconstructing diet, energy, and protein sources.
• Experimental animal data is crucial for developing new dietary reconstruction models.

Observation:

• Plotting delta13C(collagen) against delta13C(apatite) reveals three regression lines (C3, C4, marine) indicating diet protein type.
• Position on these lines signifies the energy source (C3, C4, or mixed), independent of body size or trophic level.
• Modern terrestrial fauna deviate from the model due to fermentation metabolism, unlike experimental animals.

Findings:

• Archaeological human data aligns with the model, accurately reflecting known diets from associated flora and fauna.
• Specific case studies demonstrate the model's precision: Cahokia populations (deer, nuts, maize), Ontario agriculturists (fish), Grasshopper Pueblo (turkeys), Tierra del Fuego (terrestrial vs. coastal fauna), South African Cape (C3 vs. marine protein), and San Nicolas Island (C4 plants).

Implications:

• This novel regression model provides more detailed and precise dietary reconstructions than individual isotopic measures.
• It enhances our understanding of past human subsistence strategies and environmental interactions.
• The model's applicability to archaeological contexts offers a powerful tool for dietary paleoecology.