Lori E. Wright

Stable carbon and oxygen isotopes in human tooth enamel: identifying breastfeeding and weaning in prehistory.

This paper investigates the utility of stable carbon and oxygen isotopes in human dental enamel to reveal patterns of breastfeeding and weaning in prehistory. Enamel preserves a record of childhood diet that can be studied in adult skeletons. Comparing different teeth, we used delta13C to document the introduction of solid foods to infant diets and delta18O to monitor the decline of breastfeeding. We report enamel carbonate delta13C and delta18O of 33 first molars, 35 premolars, and 25 third molars from 35 burials from Kaminaljuyú, an early state in the valley of Guatemala. The skeletons span from Middle Preclassic through Late Postclassic occupations, ca. 700 B.C. to 1500 A.D. Sections of enamel were removed from each tooth spanning from the cusp to the cemento-enamel junction. Stable isotope ratios were measured on CO2 liberated by reaction of enamel with H3PO4 in an automated carbonate system attached to a VG Optima mass spectrometer. Within a skeleton, teeth developing at older ages are more enriched in 13C and more depleted in 18O than teeth developing at younger ages. Premolars average 0.5/1000 [corrected] higher in delta13C than first molars from the same skeleton (P = 0.0001), but third molars are not significantly enriched over premolars. The shift from first molars to premolars may be due to the shift to solid foods from lipid-rich milk. After 2 years, when premolars begin to mineralize, the delta13C in childhood diets did not change systematically. First molars and premolars are similar in delta18O, but third molars average 0.7/1000 [corrected] lower than first molars (P = 0.0001) and 0.5/1000 [corrected] lower than premolars (P = 0.0003). First molar and premolar delta18O is heavier, because breast milk is more enriched in 18O than is drinking water. Hence, many children continued to nurse during the period of premolar formation. Together, these results indicate that Kaminaljuyú children had begun to eat solid maize foods before the age of 2 years but continued to drink breast milk until much later.

Recent Progress in Bioarchaeology: Approaches to the Osteological Paradox

The publication of The Osteological Paradox (Wood et al., 1992, Current Anthropology, 33:343–370) a decade ago sparked debate about the methods and conclusions drawn from bioarchaeological research. Wood et al. (1992, Current Anthropology, 33:343–370) highlighted the problematic issues of selective mortality and hidden heterogeneity in frailty (susceptibility to illness), and argued that the interpretation of population health status from skeletal remains is not straightforward. Progress in bioarchaeology over the last few years has led to the development of tools that will help us grapple with the issues of this “osteological paradox.” This paper provides a review of recent literature on age and sex estimation, paleodemography, biodistance, growth disruption, paleopathology, and paleodiet. We consider how these advances may help us address the implications of hidden heterogeneity in frailty and selective mortality for studies of health and adaptation in past societies.

Human biology in the Classic Maya collapse: Evidence from paleopathology and paleodiet

We review evidence from human biology—paleopathological and isotopic paleodietary studies on ancient Maya skeletons—to assess the validity of ecological models of the Classic Maya collapse, in which elevated disease and deteriorating diet are commonly assumed. To be upheld, the health arguments of ecological models require that the Maya disease burden (1) was greater than that for many other societies and (2) increased over the span of occupation. The dietary argument requires (1) consistent change in diet from Preclassic and Early Classic Periods to the Terminal Classic and (2) increasing social divergence in diet. A correlation between diet and disease is necessary to link these arguments. Neither pathology nor isotopic data consistently support these criteria. Instead, it appears that local environmental and political factors created diversity in both disease burden and diet. In view of the human biological data, we are skeptical of ecological models as generalized explanations for the abandonment of Classic Maya sites in the southern lowlands.

Bones of the Maya: Studies of Ancient Skeletons

Includes an indexed bibliography of the first 150 years of Maya osteology. This volume pulls together a spectrum of bioarchaeologists that reveal remarkable data on Maya genetic relationship, demography, and diseases.

Bioarchaelogical evidence for social and temporal differences in Diet at Piedras Negras

In this bioarchaeological study of Classic Maya subsistence, we analyzed porotic hyperostosis, dental caries, and stable isotopes on skeletal remains recovered from 118 burials at Piedras Negras, Guatemala. The abundant porotic hyperostosis and dental caries at Piedras Negras, coupled with a high mean ?13C (mean -9.2 ? 1.0%c) provide evidence for high levels of maize consumption. The isotope data show slight differences among social status groups. Chronological changes in diet are more evident. The Early Classic (A.D. 350?625) skeletons are characterized by moderate heterogeneity in isotope ratios relative to skeletons of the Yaxche phase of the Late Classic (A.D. 625-750). In Yaxche phase skeletons, a prosperous time for Piedras Negras, 813C and S15N are homogenous, with an emphasis on dietary maize and terrestrial fauna. In Chacal haaz times (A.D. 750-825) isotope signatures became much more diverse, with some individuals consuming less maize and/or more freshwater fish. We attribute these changes to significant perturbations in the system of food production and distribution at Piedras Negras in the late eighth century, a process that may have been linked to the disintegration of dynas tic kingship at the site and its collapse.

Biological Perspectives on the Collapse of the Pasión Maya

This paper reviews bioarchaeological research that aimed to test the biological correlates of ecological explanations for the Maya collapse using human skeletal remains from five sites in the Pasion region. Stable isotope ratios of bone collagen and alkaline earth ratios in bone minerals do not support the expectation of increased reliance on maize and declining meat consumption during the final years of Pasion occupation. Moreover, skeletal pathology does not illustrate any increment in anemia, infectious disease, or dental growth disruption that is predicted to have been a consequence of high population density and deteriorating nutrition. Instead, changes in the social distribution of foods during the Terminal Classic supports the mounting evidence that the Pasion collapse was fueled more by sociopolitical transformations than environmental ones.

ANCIENT AND MODERN MAYA EXPLOITATION OF THE JUTE SNAIL (PACHYCHILUS)

Although the economic basis of the ancient lowland Maya civilization was principally maize agriculture, throughout their long history the Maya remained prof cient fishers, hunters, and gatherers. Research increasingly has suggested early and extensive Maya exploitation of the freshwater molluscan species Pachychilus, called jute by the modern Maya. This report reviews archaeological evidencefor use of this stream- and river-dwelling invertebrate and summarizes recent data from the site of Pacbitun, in western Belize. Pachychilus not only was usedfor dietary purposes, but occasionally was included in Maya ritual deposits. Ecological information on the habitat of Pachychilus is given, as well as a description of its nutritional value and contemporary methods of collecting and processing jute in the modern Maya community of San Antonio (Cayo), Belize. It is concluded that Pachychilus was one minor but widespread element of the ancient Maya subsistence regime.

IN SEARCH OF YAX NUUN AYIIN I: Revisiting the Tikal Project's Burial 10

Recent epigraphic decipherments suggest that the child of a Teotihuacan ruler was installed as the ruler of Tikal in a.d. 379. This paper reviews the excavation and osteology of the tomb of this king, Yax Nuun Ayiin I. Estimating the age at death of the skeletons, I found that the skeletons surrounding the principal occupant include at least one adult, who was distinguished by a rare style of dental decoration. I report strontium isotope ratios obtained from the teeth of four of these skeletons. Comparison with a larger data set of strontium isotope ratios on Tikal burials indicates that none of the sampled skeletons from Burial PTP-010 were foreigners to the Maya Lowlands. Although native Tikal children cannot be distinguished from the skeletons of children who lived at nearby Peten sites using strontium isotopes, these results do not support epigraphic readings that identify Yax Nuun Ayiin as a child of Teotihuacan.

Stresses of conquest: A study of Wilson bands and enamel hypoplasias in the Maya of Lamanai, Belize

This paper examines the prevalence of Wilson bands and hypoplasias in the dental enamel of a sample of Postclassic and Historic Maya Indian remains from the archaeological site of Lamanai, Belize. Mandibular canines were removed from 23 individuals from the two periods. The surface of a polished, acid etched, longitudinal section of each canine was examined with scanning electron microscopy for the presence of enamel malformations.

Strontium Isotopes and the Study of Human Mobility Among the Ancient Maya

The present chapter on strontium isotopes from human dental enamel aims at presenting four archaeological case studies to illustrate the anthropological significance and range of applications of this technique: a northern Maya origin for the founder of Copan, a local king from Tikal, and the regional origin of two of Palenque’s rulers. The results show that isotopic variation within the various culturally important regions of Mesoamerica is generally much less than variation among the different regions. Thus analysis of strontium isotope ratios in dental enamel, which retains the ratio of the place of childhood residence, can be used not only to indicate mobility but also on occasion to determine the geographic origin of the individual.