Dr Geraldine Fahy
Dr Geraldine Fahy is a biological anthropologist specialising in the use of stable isotope analysis to answer a range of questions related to diet, disease and identification. Her educational and professional background, while soundly based in physical anthropology, analytical chemistry and forensic science, is diverse. Diversity notwithstanding, her experience and research interests fall within two thematic categories:
- biological aspects of forensic science and forensic anthropology and identification
- human evolution and behaviour, specifically human dietary ecology in relation to changing patterns of resource exploitation of plants and animals.
Geraldine has both theoretical knowledge and practical experience of physical and forensic anthropology, bioarchaeology and analytical chemistry; she has worked internationally with the United Nations in a forensic capacity, and domestically as a commercial osteoarchaeologist. She obtained her PhD from the University of Leipzig, Germany (2014) having completed her PhD research at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA). Subsequently, Geraldine worked as a post-doctoral researcher at the Centre for Archaeological Sciences, KU Leuven (Belgium), where her research surrounded the reconstruction of dietary ecology and migration patterns, using stable isotope analysis (SIA) from a range of archaeological populations spanning large timescales and geographical regions (eg populations from Classical-Hellenistic Turkey to medieval Belgium).
Her teaching and research interests at the University of Kent are wide-ranging: from forensic anthropology, human osteology, field recovery methods, analytical methods in anthropology, specifically stable isotope analysis, to dietary reconstruction in human prehistory and evolution, and primatology.
- How can SIA help trace the evolution of diet?
- Can the movement of people and animals be identified using SIA?
- How accurate is SIA at identifying the cessation of lactation and subsequently length of weaning?
- What information can be gleaned on the diet of non-human primates using SIA?
- Are there identifiable differences between sites, specifics and sexes?
- Can SIA be employed to assist identification on a large scale (eg aviation incidents, genocide, etc…)?
Trauma and disease
- Do isotope ratios vary in bone collagen affected by pathology and/or disease?
Specific ongoing projects include the following:
- Bone deep: multi-disciplinary investigation of turnover rates in adult human bone
- Dietary reconstruction using C, N & S isotope analysis spanning 1600 years (Classical-Hellenistic to Middle Byzantine) of occupation at Sagalassos, SW Turkey. Collaboration with the Centre for Archaeological Sciences, KU Leuven & the Max Planck Institute for Evolutionary Anthropology, Leipzig
- Dietary reconstruction using C, N & S isotope analysis on human skeletal remains from medieval Tongeren (Belgium). Collaboration with the Centre for Archaeological Sciences, KU Leuven, and the Department of Anthropology, University of Cape Town, South Africa.
- Dietary reconstruction using C, N & S isotope analysis on human skeletal remains from medieval Tournai (Belgium). Collaboration with the Centre for Archaeological Sciences, KU Leuven, and the Department of Anthropology, University of Cape Town, South Africa.
- Aspects of early medieval lifestyle in Eastern Europe: stable isotope evidence of diet, maternal investment & social status in Bulgaria. Collaboration with the Bulgarian Academy of Sciences and the University of Reading.
- Reconstruction of chimpanzee dietary ecology in neighbouring National Parks (Sapo National Park, Liberia & Taï National Park, Côte d’Ivoire). Collaboration with the Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig.
- SE561: Biology and Human Identity (module convenor)
- SE609: Forensic Anthropology (module convenor)
- SE302: Foundations of Biological Anthropology
- SE533: Project in Anthropological Science
- SE567: Methodology in Anthropological Science
- SE307: Thikers and Theories: An Introduction to the History and Development of Anthropology
- SE570: Current Issues in Evolutionary Anthropology
Dr Fahy can offer supervision of PhD and MA/MSc students within any of her areas of interest – stable isotope analysis, dietary ecology, human identification, specifically forensic anthropology and mass disaster victim identification.
Ana Curto: ‘The impact of diet and health on bone stable isotope ratios: A comparative study’ (University of Kent 50th Anniversary Scholarship recipient)
Dr Fahy is available to provide topical comment or in-depth discussion of topics related to forensic anthropology, disaster victim identification, human evolution, dietary reconstruction and stable isotope analysis.
Curto, A. et al. (2018). Did military orders influence the general population diet? Stable isotopes analysis from Medieval Tomar, Portugal. Archaeological and Anthropological Sciences [Online]. Available at: https://doi.org/10.1007/s12520-018-0637-3.This study integrates bone collagen stable isotope data (carbon, nitrogen and sulphur) from 33 human adult tibiae (15 females; 18 males) and 13 faunal remains from Tomar, while it was under the Military Orders domain (11th – 17th centuries). Historical literature indicates that the amount of meat consumption among Templars was lower than in individuals with similar social status. In medieval times these Military Orders had total control of towns and angling and fishing rights, but their influence on the general population diet remains unknown. While no statistically significant differences (p>0.05) were found between sexes, social status, or for bone collagen δ13C and δ34Sbetween age groups, δ15N did differ significantly with age, which may be related to tooth loss in old individuals. Additionally, the human samples have higher stable isotope differences, in comparison to faunal samples, than would be expected within the food web, particularly for δ13C. This human bone collagen δ13C enrichment may reflect a diet rich in aquatic protein intake, which is also supported by δ34S archived in human and faunal samples, and the presence of oysters and cockles shells at the excavation. The religious diet restrictions might have led to a higher intake of aquatic protein when meat consumption was not allowed.
Fahy, G. et al. (2017). Bone deep: variation in stable isotope ratios and histomorphometric measurements of bone remodelling within adult humans. Journal of Archaeological Science [Online] 87:10-16. Available at: https://doi.org/10.1016/j.jas.2017.09.009.Stable carbon (δ13C) and nitrogen (δ15N) isotope studies of ancient human diet increasingly sample several skeletal elements within an individual. Such studies draw upon differences in bone turnover rates to reconstruct diet during different periods of time within an individual’s lifetime. Rib and femoral bone, with their respectively fast and slow remodeling rates, are the bones most often sampled to reconstruct shorter and longer term signals of diet prior to death. It is poorly understood if δ13C and δ15N vary between bone types within a single individual, or if this variation corresponds with bone turnover rate (BTR). Here, we determined δ13C and δ15N for ten different bones from ten adult human skeletons (n=5 males; n=5 females). Isotope values were compared to the rate that each bone remodeled, calculated from osteon population (OPD) density. Results reveal that isotope ratios varied within each skeleton (δ13C: max= -1.58‰; δ1542 N: max= 3.05‰). Humeri, metacarpals, and ribs had the highest rate of bone remodelling; the occipital bone had the lowest. A regression analyses revealed that higher rates of bone remodeling are significantly and negatively correlated with lower δ15N. Our results suggest that the occipital bone, with its slow rate of bone renewal, may prove useful for isotopic studies that reconstruct diet over longer periods of time within an individual’s lifetime. Isotope studies that compare individual skeletal elements between populations should standardize their methodology to bones with either a slow or fast turnover rate.
Oetze, V. et al. (2016). Comparative Isotope Ecology of African Great Apes. Journal of Human Evolution [Online] 101:1-16. Available at: http://dx.doi.org/10.1016/j.jhevol.2016.08.007.The isotope ecology of great apes is a useful reference for palaeodietary reconstructions in fossil hominins. As extant apes live in C3 dominated habitats, variation in isotope signatures is assumed to be low compared to hominoids also exploiting C4-plant resources. However, isotopic differences between sites and between and within individuals were poorly understood due to the lack of vegetation baseline data. In this comparative study we included all species of free-ranging African great apes (Pan troglodytes, Pan paniscus, Gorilla gorilla gorilla and Gorilla beringeri beringei). We explore differences in isotope baselines across different habitats and how isotopic signatures in apes can be related to feeding niches (faunivory and folivory). Secondly, we illustrate how stable isotopic variation within African ape populations compares to other primates, including hominins from the fossil record, and discuss possible implications for dietary flexibility. Using 815 carbon and nitrogen isotope data from 155 sectioned hair samples and an additional collection of 189 fruit samples we compare six different great ape sites. We investigate the relationship between vegetation baselines and climatic variables, and subsequently correct great ape isotope data to a standardized plant baseline from the respective sites. We gained temporal isotopic profiles of individual animals by sectioning hair along its growth trajectory. Isotopic signatures of great apes differed between sites, mainly as vegetation isotope baselines were correlated with site-specific climatic conditions. We show that controlling for plant isotopic characteristics at a given site is essential for data interpretation. When controlling for plant baseline effects, we found distinct isotopic profiles for each great ape population. Based on evidence from habituated groups and sympatric great ape species these differences could be related to faunivory and folivory. Dietary flexibility in extant apes varies between species and populations, but temporal isotopic variation was overall lower than in species shifting from C3 to C4-resources, including fossil hominins and extant primates.
Fahy, G. et al. (2015). The effectiveness of using carbonate isotope measurements of body tissues to infer diet in human evolution: Evidence from wild western chimpanzees (Pan troglodytes verus)*. Journal of Human Evolution [Online] 88:70-78. Available at: http://www.dx.doi.org/10.1016/j.jhevol.2015.09.002.Changes in diet throughout hominin evolution have been linked with important evolutionary changes. Stable carbon isotope analysis of inorganic apatite carbonate is the main isotopic method used to reconstruct fossil hominin diets; to test its effectiveness as a paleodietary indicator we present bone and enamel carbonate carbon isotope data from a well-studied population of modern wild western chimpanzees (Pan troglodytes verus) of known sex and age from Taï, Cote d'Ivoire.We found a significant effect of age class on bone carbonate values, with adult chimpanzees being more 13C- and 18O-depleted compared to juveniles. Further, to investigate habitat effects, we compared our data to existing apatite data on eastern chimpanzees (P. troglodytes schweinfurthii) and found that the Taï chimpanzees are significantly more depleted in enamel d13Cap and d18Oap compared to their eastern counterparts. Our data are the first to present a range of tissue-specific isotope data from the same group of wild western chimpanzees and, as such, add new data to the growing number of modern non-human primate comparative isotope datasets providing valuable information for the interpretation of diet throughout hominin evolution. By comparing our data to published isotope data on fossil hominins we found that our modern chimpanzee bone and enamel data support hypotheses that the trend towards increased consumption of C4 foods after 4 Ma (millions of years ago) is unique to hominins.
Fahy, G. et al. (2014). Stable Nitrogen Isotope Analysis of Dentine Serial Sections Elucidate Sex Differences in Weaning Patterns of Wild Chimpanzees (Pan troglodytes). American Journal of Physical Anthropology [Online] 153:635-642. Available at: http://dx.doi.org/10.1002/ajpa.22464.Offspring provisioning is one of the most energetically demanding aspects of reproduction for female mammals. Variation in lactation length and weaning strategies between chimpanzees (Pan troglodytes), our closest living relative, and modern human societies have been reported. When and why these changes occurred is frequently debated. Our study used stable nitrogen isotope data of tooth root dentine from wild Western chimpanzees (Pan troglodytes verus) in Tai National Park, C^ote d’Ivoire, to quantify weaning in these chimpanzees and explore if infant sex plays a role in maternal investment. We analyzed serial sections of deciduous lateral incisor root dentine from four Tai chimpanzees to establish the d15N signal of nursing infants; we then analyzed serial sections of first permanent mandibular molar root dentine from 12 Tai chimpanzees to provide quantitative d15N data on weaning in this population. Up to 2 years of age both sexes exhibited dentine d15N values 2–3% higher than adult female Tai chimpanzees, consistent with a nursing signal. Thereafter a steady decrease in d15N values consistent with the onset, and progression, of weaning, was visible. Sex differences were also evident, where male d15N values decreased at a significantly slower rate compared to females. Confirmation of sex differences in maternal investment among Tai chimpanzees, demonstrates the viability of using isotope analysis to investigate weaning in non-human primates. Additionally, assuming that behaviors observed in the Ta€ı chimpanzees are illustrative of the ancestral pattern, our results provide a platform to enable the trajectory of weaning in human evolution to be further explored.
Fahy, G. et al. (2013). Stable isotope evidence of meat eating and hunting specialization in adult male chimpanzees. Proceedings of the National Academy of Sciences [Online] 110:5829-5833. Available at: http://dx.doi.org/10.1073/pnas.1221991110.Observations of hunting and meat eating in our closest living relatives, chimpanzees (Pan troglodytes), suggest that among primates, regular inclusion of meat in the diet is not a characteristic unique to Homo. Wild chimpanzees are known to consume vertebrate meat, but its actual dietary contribution is, depending on the study population, often either unknown or minimal. Constraints on continual direct observation throughout the entire hunting season mean that behavioral observations are limited in their ability to accurately quantify meat consumption. Here we present direct stable isotope evidence supporting behavioral observations of frequent meat eating among wild adult male chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d’Ivoire. Meat eating among some of the male chimpanzees is significant enough to result in a marked isotope signal detectable on a short-term basis in their hair keratin and long-term in their bone collagen. Although both adult males and females and juveniles derive their dietary protein largely from daily fruit and seasonal nut consumption, our data indicate that some adult males also derive a large amount of dietary protein from hunted meat. Our results reinforce behavioral observations of male-dominated hunting and meat eating in adult Taï chimpanzees, suggesting that sex differences in food acquisition and consumption may have persisted throughout hominin evolution, rather than being a recent development in the human lineage.