A Study of the Potential of Deciduous Incisor Wear as an Indicator of Weaning Using a Human Skeletal Population

The aim of this work is to investigate the potential of wear on the earliest erupting teeth, the deciduous central incisors, for studying weaning in human skeletal populations. The study group is from mediaeval Wharram Percy, where existing δ¹⁵N data indicate cessation of breastfeeding occurred by about 24 months post‐partum. The hypothesis tested is that there should be an increase in dental wear as breast milk is replaced with solid foods during weaning. Incisor wear is monitored using crown heights, measured from photographs using image analysis. Results provide little evidence for alteration in incisor wear rates with the attenuation of breastfeeding, perhaps because abrasive foods were used as supplements well before breastfeeding declined. Copyright © 2015 John Wiley & Sons, Ltd.     

Mummies, maize, and manure: multi-tissue stable isotope analysis of late prehistoric human remains from the Ayacucho Valley, Perú

This paper reports the δ¹³C and δ¹⁵N values of bone collagen, muscle and skin from several late prehistoric–early colonial (AD 1490–1640) mummies from Perú's Ayacucho Valley. The mean of the δ¹³C and δ¹⁵N values of bone collagen are −11.5 ± 1.4 and 11.1 ± 0.7‰, respectively. The mean of the δ¹³C values for Vinchos skin is −11.8 ± 1.2‰ and the mean of δ¹⁵N values is 13.2 ± 0.5‰. The samples of muscle tissue have a δ¹³C mean of −11.9 ± 0.9‰ and a δ¹⁵N mean of 12.7 ± 0.3‰. The data from bone collagen indicate maize was the basis of the region's subsistence economy. A significant correlation between δ¹³C and δ¹⁵N values of bone collagen (R² = 0.75) is consistent with the preferential fertilization of maize with composted manure. Both skin and muscle samples are consistently enriched in δ¹⁵N relative to paired samples of bone (2.1 ± 0.5 and 1.6 ± 0.7‰, respectively), possibly as a result of short term physiological stress or differential decomposition.     

Taxonomic, anatomical, and spatio-temporal variations in the stable carbon and nitrogen isotopic compositions of plants from an African savanna

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios are commonly used to reconstruct palaeodiets and palaeoenvironments. The method is based on our knowledge of isotopic patterns in plants, which are subject to taxonomic and environmental variability. While previous researchers have addressed isotopic variability amongst plants, no studies have looked extensively at a broad suite of taxa over multiple temporal scales from within the savanna biome so as to provide baseline data for palaeodietary and palaeoenvironmental studies. Here we document variations in the isotopic compositions of plants collected over two years from the Kruger National Park, South Africa, with respect to species and anatomical differences, and the influences of geological substrate and spatio-temporal shifts in climate. Results show that environmentally-induced carbon isotopic variations in plants within this region are generally smaller than 2‰, which is lower than what has been previously reported for plants compared across multiple habitat-types. These data suggest that δ¹³C differences of 2‰ or more (or 1‰ if the diet is predominantly C₄) between animals from a given area reliably indicate real dietary differences. Plant δ¹⁵N values vary greatly between different microhabitats (by up to 4‰), responding to a range of environmental influences that may, in turn, significantly influence variation in animal δ¹⁵N values.     

Human and animal diet at Conchopata, Peru: stable isotope evidence for maize agriculture and animal management practices during the Middle Horizon

This paper reports δ¹³C and δ¹⁵N values for human and animal skeletal remains from the Middle Horizon (AD 550–1000) site of Conchopata in the Peruvian highlands. The data indicate that maize was the dietary staple for both humans and the majority of animals at this urban site. Camelids at the site segregated into two groups according to δ¹³C values, reflecting two distinct animal management strategies. Human infants were found to have elevated δ¹⁵N values, reflecting the trophic level effect of breastfeeding. No sex based differences in diet were observed.     

An experimental study of nitrogen flux in llamas: is N preferentially excreted?

Nitrogen isotope analysis is now commonly used to investigate the diets, and to a lesser extent, the environments of ancient populations. These studies assume that mammals are predictably enriched in ¹⁵N over their food, and concomitantly, that ¹⁵N becomes increasingly concentrated as one moves up the food chain. The literature commonly states that this ¹⁵N-enrichment of mammalian tissues is due to preferential excretion of light nitrogen (¹⁴N), but there are few data to support this assertion. To address the gap, we conducted two nitrogen flux trials in which four llamas (Lama glama) were fed high- and low-protein diets. The ratios of fecal nitrogen loss to urinary nitrogen loss were 0.30 and 0.88 on the high- and low-protein diets respectively. Feces were enriched in ¹⁵N by approximately +3‰ on both diets, whereas urinary nitrogen was depleted in ¹⁵N (−2.1‰) on the low-protein diet, but not significantly different from intake δ¹⁵N on the high-protein diet. Most importantly, there was no statistically significant difference between dietary and total excreta δ¹⁵N on either diet. Given these data and theoretical considerations, we argue that the nitrogen influx and efflux of adult mammals at steady state should be isotopically commensurate. However, during growth, diet change, thermal or nutritional stress, animals may not be at steady state and fractionation between intake and excreta δ¹⁵N may occur.     

Investigating foetal and perinatal mortality in prehistoric skeletal samples: a case study from a 3000-year-old Pacific Island cemetery site

The Teouma skeletal sample from Vanuatu represents one of the few truly colonising populations in the Pacific Islands. Therefore, investigating the factors that may have affected foetal/infant mortality in this population is potentially important for understanding the success of settlement in this region of the world. We investigate whether stable isotope analyses of carbon and nitrogen in conjunction with skeletal ageing techniques, can aid in identifying whether the subadults from Teouma died before or after birth in an attempt to understand the potential threats to foetal and infant survival. Multiple skeletal ageing methods using diaphyseal lengths were used to age the young subadults (n = 7). Using regression-based skeletal ageing methods, four of the individuals were aged at around full-term gestation (37–42 weeks gestation), while the remaining three individuals died preterm. The isotope analyses did not assist in identifying the individuals that survived post-birth because none of the subadults displayed the 2–3‰ trophic increase in δ¹⁵N values expected for a breastfed infant, probably as a result of their young age. However, all of the foetal/perinatal individuals exhibited higher δ¹⁵N values in their bone collagen compared with the adult females of the sample, with two of the individuals demonstrating unusually high δ¹⁵N values. The δ¹³C values of the foetuses/perinates did not exhibit the same variation. We explore a number of possible explanations for this elevation of perinatal/foetal δ¹⁵N values and tentatively suggest that this is a result of in utero stress as a consequence of chronic maternal ill-health. The osteological and palaeodemographic evidence supports the assertion that females, foetuses and perinates were susceptible to environmental stress within this colonising population, resulting in early death of the perinatal individuals in addition to early terminations of pregnancy or premature birth possibly caused by infectious and/or metabolic diseases.     

The Seaweed FlyThoracochaeta zosterae(Hal.) (Diptera: Sphaerocidae) in Inland Archaeological Contexts: δC and δN Solves the Puzzle

The presence of the flyThoracochaeta zosteraein cesspits had led to the unlikely interpretation that seaweed had been present in Mediaeval cesspitis. Archaeological and modern pupae fromT. zosteraewere sampled along with their probable larval diets (extracted plant material from cesspit and seaweed, respectively). The spacing between pupae and food for δ¹³C and δ¹⁵N was similar for both modern and archaeological samples. Modern pupae had isotopic ratios typical for marine invertebrates for δ¹³C. Archaeological puparia had isotopic values typical for terrestrial grazers (i.e., non-marine), indicating that there was no marine inclusion in the cesspits.     

Stable carbon isotope analysis of human tooth enamel from the Bronze Age cemetery of Ya'amoun in Northern Jordan

Seventy-five teeth from the Bronze Age cemetery of Ya'amoun were sampled for carbon isotope analysis. The sampled teeth represented the transitional period of the Middle/Late Bronze Age. The results showed that the components of the diet that are reflected in the carbon isotope data remained the same during this period with an average δ¹³C of about −11.87‰. This value reflects more C₃ plant consumption.     

Variations in the C/C ratios of modern wheat grain, and implications for interpreting data from Bronze Age Assiros Toumba, Greece

Variations in the ¹³C/¹²C ratios of wheat grain at different spatial and temporal scales are examined by analysis of modern samples, including harvests of einkorn and durum wheat from Greece, and serve as a guide to interpreting data for Bronze Age grains from Assiros Toumba. The normal distribution and low variability of δ¹³C values of einkorn from 24 containers in the Assiros storerooms are consistent with pooling of local harvests, but less likely to represent the harvest of several years or include grain imported from further afield. Correlation between emmer and spelt δ¹³C values provides strong support for other evidence that these were grown together as a maslin crop. ¹³C discrimination (Δ) for the Bronze Age samples is estimated to be 2.5‰ larger than at present, and would be consistent with an intensive, horticultural regime of cereal cultivation, possibly involving some watering.     

Dietary patterns and social structures in medieval Sigtuna, Sweden, as reflected in stable isotope values in human skeletal remains

Stable isotopes (δ¹³C, δ¹⁵N) have been studied in human burials from the medieval town Sigtuna in Sweden. Dietary patterns of 80 adult individuals were analyzed on three cemeteries representing the phases of establishment, prosperity and decline of the town. All analyzed individuals were radiocarbon dated. One of the cemeteries, Church 1, represents a population of higher social status than those at the other two cemeteries.The δ¹³C values are homogenous and showed that the protein intake was mainly of terrestrial origin in the whole population. δ¹⁵N values varies more and they may indicate a higher input of vegetables in the diet at one of the cemeteries, the Nunnan block.Already in the initial phases of Sigtuna a social hierarchy had been established which is reflected in dietary patterns. Apparently more animal protein was consumed among the high status population of the town. Furthermore, differences in dietary patterns between the sexes were noted. In all phases the females show more clustered values indicating a more homogeneous diet than that of the males.     

A Late Holocene vertebrate food web from southern Haida Gwaii (Queen Charlotte Islands, British Columbia)

This study presents isotopic data (δ¹³C and δ¹⁵N from bone collagen) for 104 samples representing 29 vertebrate taxa from late pre-contact through to contact era (ca. 2000 – 100 BP) Haida Gwaii (British Columbia, Canada) from a wide variety of mostly marine organisms. The results demonstrate the considerable isotopic variability that characterizes potential prey items in coastal contexts and underscores the need for baseline faunal data to interpret human subsistence practices. Based on these data, a detailed marine food web was constructed, which provides insight into local ecological conditions. We present a simple method for quantifying the trophic level of ancient fauna using δ¹⁵N of bone collagen. Finally, we discuss the implications of this study for the reconstruction of human diet.     

Coast–inland mobility and diet in the Danish Mesolithic and Neolithic: evidence from stable isotope values of humans and dogs

Here we present the stable isotope ratios of carbon and nitrogen measured in bone collagen extracted from humans, dogs, herbivores and fish from Mesolithic and Neolithic coastal and inland sites in Denmark. Bones of freshwater fish from several Early Mesolithic lake-side sites have δ¹³C values surprisingly similar to those seen in marine fish. We propose a model, based on δ¹³C and δ¹⁵N, for the correction for both marine and hard water reservoir effect in radiocarbon dates. A strong reliance on aquatic protein is demonstrated for the Mesolithic inhabitants of the region from the middle of the Early Mesolithic onwards. A significant part of the protein in the diets of the dogs and humans from the Middle and Late Mesolithic was of marine origin, even at inland sites. This observation points to a high degree of (seasonal) coast-inland mobility. The isotopic evidence indicates that during the Neolithic small quantities of aquatic foods were still common sources of dietary protein.     

Intra‐individual variation in stable carbon (δ13C) and nitrogen (δ15N) isotopes in mandibles of modern caribou of Qamanirjuaq (Rangifer tarandus groenlandicus) and Banks Island (Rangifer tarandus pearyi): Implications for tracing seasonal and temporal changes in diet

Intra‐individual variations in carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope measurements of dentine collagen in ungulate teeth can be related to diet and environmental changes at different periods during the life of the animal. A protocol of serial sampling of first, second and third molar roots was applied to modern caribou (17–27 months old) of the Qamanirjuaq herd (Rangifer tarandus groenlandicus), Canada. Based on a previous study, we predicted that M2 would reflect winter, M3 summer and M1 a complete year in terms of the isotopic record. Relatively high δ¹⁵N values (ca. 6 to 8‰), previously attributed to winter stress, were found in different molars of different specimens, reflecting a period of growth between April 1966 to April 1967. Previous results on other teeth from the same population confirmed that a high δ¹⁵N_coll value signal corresponded to the winter of 1966/67. This temporary increase in δ¹⁵N value was probably linked to diet and/or environmental change. Collagen from M1 reflects the first winter whereas M2 and M3 reflect the second winter of life of young caribou. A longer time record including summer is represented by the bone collagen of the mandible. Results obtained on molar roots and mandible bone of the modern caribou of Banks Island herd (Rangifer tarandus pearyi) confirmed this seasonal record. Such collagen isotopic analysis on M1, M2 and M3 roots and jawbone can be applied to reindeer found in archaeological sites. Mandibles retaining deciduous premolars are preferable to avoid the possible loss of the winter tooth signal observed in animals older than 2 years. Copyright © 2010 John Wiley & Sons, Ltd.     

Detection of Dietary Changes by Intra-tooth Carbon and Nitrogen Isotopic Analysis: An Experimental Study of Dentine Collagen of Cattle (Bos taurus)

Hypsodont teeth potentially contain a record of dietary or environmental changes occurring during their growth. The aim of our study is to understand how a dietary change is recorded in dentine collagen. Analyses were conducted on five steers (Bos taurus) raised in an experimental farm. From birth until weaning the steers were fed on a C₃diet; after weaning they were fattened on a C₄/C₃mixed diet until slaughter. Dentine collagen was sampled on demineralized molars from top to bottom. The change from the C₃to the C₄/C₃diet and weaning are both reflected in intra-tooth variations in δ¹³C and δ¹⁵N values, respectively. The abrupt change in carbon isotopic composition of the diet is reflected by a progressive change of the dentine collagen δ¹³C values. The gradual change may reflect sampling strategy and/or gradual turnover of the metabolic nutrient pool. The weaning process is reflected by a decrease in δ¹⁵N that exactly coincides with increase in δ¹³C. This demonstrates that when steers are weaned to a protein-poor diet, δ¹⁵N traces the cessation of suckling. Archaeological applications of this study are considered, including determination of the duration of lactation in prehistoric herds, and detection of residential mobility in cattle herders.     

The Whole Tooth and Nothing but the Tooth: Or why Temporal Resolution of Bone Collagen May Be Unreliable

The carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios of human bone collagen have been used extensively over the last 40 years to investigate the diet of past populations. It has become apparent that bone collagen can give an unreliable temporal dietary signature especially in juveniles. With higher temporal resolution sampling of collagen from tooth dentine, it is possible to identify short-term changes in diet previously invisible in bone. This paper discusses the inherent problems of using bone collagen for dietary studies and suggests better sample choices, which can make our interpretations more robust, using breastfeeding and weaning as an example.     

Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany

The first appearance of the Neolithic Linearbandkeramik (LBK) in Central Germany occurred during the 6th millennium BC. However, though LBK sites are abundant in the German loess areas, there are only a few studies that reconstruct the diet of these first farmers using biochemical methods. Here we present the largest study undertaken to date on LBK material using stable isotope analysis of carbon and nitrogen to reconstruct human diet and animal husbandry strategies. We analyzed the bone collagen of 97 human individuals and 45 associated animals from the sites of Derenburg, Halberstadt and Karsdorf in the Middle Elbe–Saale region of Central Germany. Mean adult human values are ?19.9 ± 0.4‰ for δ¹³C and 8.7 ± 0.8‰ for δ¹⁵N. The δ¹³C values are typical for terrestrial, temperate European regions, whereas the δ¹⁵N values fall within an expected range for farming societies with a mixed diet consisting of products from domestic animals and plants. The consumption of unfermented dairy products is unlikely as there is direct palaeogenetic evidence of lactose intolerance available for one of the sites. There are no clear indications for dietary differences in sex. Young children under three years of age are enriched in δ¹⁵N due to breastfeeding indicating that weaning likely occurred around the age of three years. The fauna exhibit mean δ¹³C values of ?20.9 ± 0.8‰ and mean δ¹⁵N values of 7.0 ± 0.9‰ respectively. Variation in the δ¹³C and δ¹⁵N in the domestic animals is probably caused by different livestock managements.     

Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

Directional asymmetry in the human clavicle

The human right clavicle tends to be shorter than the left. A range of possible explanations can be advanced to account for this asymmetry. In the present work, clavicular morphology was studied in a medieval skeletal assemblage from Wharram Percy, England, with the aim of evaluating these competing explanations. At Wharram Percy, as anticipated, the right clavicle tended to be shorter. Patterns of asymmetry in curvature, robusticity, vascularization, and in the morphology of ligament and muscle attachment sites were also studied. The patterning in these data at Wharram Percy is consistent with inhibition of longitudinal growth of the clavicle on the dominant side due to lateral bias in mechanical loading, particularly in axial compression. Copyright © 1999 John Wiley & Sons, Ltd.     

Shell-gathering from mangroves and the seasonality of the Southeast Asian Monsoon using high-resolution stable isotopic analysis of the tropical estuarine bivalve (Geloina erosa) from the Great Cave of Niah, Sarawak: methods and reconnaissance of molluscs of early Holocene and modern times

This paper describes a reconnaissance, high-resolution, study of stable isotopes (δ¹⁸O and δ¹³C) from modern shells of the estuarine bivalve Geloina erosa, and those dated to the early Holocene that were harvested by people from mangroves near the Great Cave of Niah on the north coast of Borneo. This reconnaissance study provides high-resolution palaeoclimatic-palaeohydrological information concerning early human activity in the region and the past character of the Southeast Asian Monsoon. Laser ablation continuous flow isotope ratio mass spectrometry (LA-CF-IRMS) on modern shells of Geloina erosa revealed ‘saw-tooth’ stable isotopic profiles that bear a close resemblance to peaks and troughs of trends in recent local rainfall, including the 1998 El Niño drought, highlighting the potential of Geloina erosa for reconstructing seasonality of the Southeast Asian Palaeomonsoon. LA-CF-IRMS analysis of prehistoric shells of Geloina erosa held in the Harrisson Archives of the Sarawak Museum revealed cyclical shifts in δ¹⁸O with similar amplitudes of variation as found in modern shells of Geloina erosa. As at the present day, this probably reflects the changing seasonality of the monsoon rains with shifts to negative δ¹⁸O values during periods of high runoff. Lighter mean δ¹⁸O values of the prehistoric shells, however, may indicate a greater annual surplus of rainfall and possibly consistent with the early Holocene strengthening of the summer monsoon at that time. The similarity of the last growth increment δ¹⁸O of the prehistoric shells to their mean δ¹⁸O profile values suggests that gathering took place during times of moderate runoff.     

Correlation BetweenC Ages and Aspartic Acid Racemization at the Upper Palaeolithic Site of the Abri Pataud (Dordogne, France)

The Upper Palaeolithic site of the Abri Pataud (Dordogne, France) has been the subject of numerous¹⁴C age determinations which cover the period from 20,400±450 years (OXA-373) to 34,250±675 years (Grn-4507). The racemization ratios of aspartic acid have been determined in 26 fossil bones. The bones are present in two different sedimentary surroundings: levels (fine deposits with numerous artefacts and fossil bones) and “éboulis” (coarse deposits derived from the neighbouring limestone cliff). Racemization ratios for total aspartic acid have a poor correlation with¹⁴C ages (respectivelyr²=0·59 and 0·82 for the two environments) but apparent racemization rates are clearly dependent on the type of deposits (levels: K=4·4×10⁻⁶year⁻¹; éboulis: K=9×10⁻⁶year⁻¹).Racemization ratios of aspartic acid in a high molecular weight protein fraction (>10,000 Da) correlate much better with¹⁴C ages (r²=0·999) for the samples from the levels (k=2·1×10⁻⁵year⁻¹). From this regression line we estimate ages for two Aurignacian levels: level 6≈29,560 years and level 9≈30,440 years .It is noteworthy that none of the regression lines intercepts the origin. Racemization of aspartic acid appears to occur only after a delay of many thousands of years. This phenomenon could be the result of a coupling between the degradation of proteins and the racemization of amino acids.