Trophic level and macronutrient shift effects associated with the weaning process in the Postclassic Maya

Area of Science:

• Paleoanthropology
• Bioarchaeology
• Maya Archaeology

Background:

• Investigating the weaning process provides insights into infant care and developmental stages in past populations.
• The Postclassic Maya sites of Marco Gonzalez and San Pedro offer a unique context for studying weaning practices.

Purpose of the Study:

• To determine the age range and dietary changes associated with weaning among Postclassic Maya infants.
• To utilize stable isotope analysis to reconstruct infant feeding practices and identify weaning stages.

Main Methods:

• Analysis of bone collagen and bioapatite from 67 Maya individuals (infants and adults).
• Application of five isotopic measures: stable nitrogen and carbon isotopes in collagen, carbon and oxygen isotopes in bioapatite, and collagen-to-bioapatite carbon isotope differences.
• Comparison of infant isotopic signatures with those of adult females to identify dietary and physiological shifts.

Main Results:

• Infant collagen nitrogen isotope ratios differed from adult females, indicating trophic level effects.
• Collagen-to-bioapatite differences and oxygen isotope ratios in infant bioapatite suggested a shift in macronutrients and breast milk consumption, respectively.
• Isotopic variations among infants pointed to deaths occurring at different stages of the weaning process, with an average weaning age of 3-4 years, beginning around 12 months.

Conclusions:

• Stable isotope analysis confirms an average weaning age of 3-4 years for Postclassic Maya infants, consistent with ethnohistoric data.
• The study highlights the utility of collagen-to-bioapatite spacing as a marker for macronutrient shifts during weaning.
• This research contributes to understanding Maya child-rearing practices and the application of isotopic methods in bioarchaeology.