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).
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
- Poor diet leads to bad health and vice versa: isotopic analysis of the impact of metabolic and infectious diseases on human skeleton. Funded by the University of Kent, Faculty of Social Sciences Research Fund.
- Skeletal health in Medieval societies (in Bone Health: A Reflection of the Social Mosaic). Collaboration with Australian National University.
- 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.
- 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: Thinkers 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., Mahoney, P., Maurer, A., Dias, C., Fernandes, T. and Fahy, G. (2019). Diet and disease in Tomar, Portugal: comparing stable carbon and nitrogen isotope ratios between skeletons with and without signs of infectious disease. Journal of Archaeological Science [Online] 105:56-69. Available at: https://doi.org/10.1016/j.jas.2019.03.005.Objectives: This study explored the correspondence between stable isotope ratios and indicators of non-specific
(periostitis and/or osteomyelitis) and specific (venereal syphilis) disease in a sample of human skeletons from a
Portuguese archaeological collection. Additionally, this study examined stable carbon (δ13C) and nitrogen (δ15N)
isotope ratios between individuals at different disease stages.
Materials and Methods: δ13C and δ15N data from previously analysed skeletons without signs of infectious disease or physiological stress (n=32) were compared to new
data from skeletons with active (n=6), healed (n=7) or a combination of both lesions (n=10). Skeletons with lesions
(n=23) were also grouped as having only healed tibial periostitis (n=7), generalised non-specific (n=5) and generalised
specific infections (n=2). The skeletons with lesions that did not fit into these groups (n=9) were not used in this
analysis. Results: The δ15N from skeletons with non-specific generalised infections in several bones differed
significantly when compared to skeletons that had either only healed tibial periostitis or were without lesions. Skeletons
with venereal syphilis had similar mean δ13C and δ15N to either skeletons without signs of disease or those with only
healed tibial periostitis.
Discussion: These results suggest different diets may be linked into an individual’s
susceptibility to these pathogens. Diet influences resistance to infectious disease, while infections decrease nutrient
availability, increase malabsorption and resting energy expenditure. Potentially therefore, combining isotopic evidence
of diet with pathology may contribute to a new understanding of health and lifestyle in the past.
Curto, A., Mahoney, P., Fahy, G., Maurer, A., Barrocas-Dias, C. and Fernandes, T. (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 ?13C and ?34Sbetween age groups, ?15N 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 ?13C. This human bone collagen ?13C enrichment may reflect a diet rich in aquatic protein intake, which is also supported by ?34S 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., Deter, C., Pitfield, R., Miszkiewicz, J. and Mahoney, P. (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 (?13C) and nitrogen (?15N) 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 ?13C and ?15N vary between bone types within a single individual, or if this variation corresponds with bone turnover rate (BTR). Here, we determined ?13C and ?15N 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 (?13C: max= -1.58‰; ?1542 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 ?15N. 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., Fahy, G., Hohmann, G., Robbins, M., Leinert, V., Lee, K., Eshuis, H., Seiler, N., Wessling, E., Head, J., Boesch, C. and KÃ¼hlH. (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., Boesch, C., Hublin, J. and Richards, M. (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., Richards, M., Fuller, B., Deschner, T., Hublin, J. and Boesch, C. (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€? 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., Richards, M., Riedel, J., Hublin, J. and Boesch, C. (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.
Miszkiewicz, J., Stewart, T., Deter, C., Fahy, G. and Mahoney, P. (2019). Chapter 2. Skeletal health in Medieval societies: insights from stable isotopes and dental histology. In: Miszkiewicz, J. J., Brennan-Olsen, S. and Riancho, J. A. eds. Bone Health: A Reflection of the Social Mosaic. Springer. Available at: http://dx.doi.org/10.1007/978-981-13-7256-8.