The late Holocene marks a period of significant population movement and subsistence change throughout much of sub-Saharan Africa. Around 3500 BP it appears that foraging populations in southernmost South Africa began to experience stress related to an increasing population and changing climatic conditions. Approximately 1500 years later a new form of subsistence - sheep herding – emerged in areas previously occupied solely by foragers, but was not exclusively adopted. The mechanisms surrounding the introduction of this new subsistence strategy – an indigenous adoption via diffusion or a foreign migration - remain unresolved. This study takes a biological approach to this significant question in southern African prehistory by exploring a collection of Later Stone Age skeletal remains that predate and postdate the appearance of pastoralism in order to determine if any significant changes in skeletal morphology indicative of population discontinuity can be identified at 2000 BP. A collection of seventy-three Later Stone Age adult skeletons (31 M, 42 F) with newly generated radiocarbon dates ranging from 8000 BP to 300 BP (uncalibrated) from the Eastern Cape Province of South Africa forms the basis of this study. Questions surrounding population continuity or discontinuity associated with the advent of sheep herding are investigated by examining metric variables collected from the cranium, post cranial skeleton and dentition, in conjunction with cranial discrete traits. Some changes in skeletal morphology are observed, but the timing, pattern and magnitude of these changes are not consistent with a foreign migration. A reduction in overall skeletal size in the absence of changes in shape corresponds with the period of forager intensification. Body size rebounds at around 2000 BP when evidence for a new form subsistence, sheep herding, is first observed in this region, suggesting that some foragers may have adopted sheep and the herding way of life as a stress relieving mechanism, while others maintained the foraging lifestyle. The timing of the observed changes in skeletal size, the absence of shape changes and the homogeneity in cranial discrete trait frequencies through time argues against the idea that sheep herding was introduced to the Cape region by outsiders. Rather, the findings of the current study suggest sheep herding was an indigenous development among existing foragers.

Le rire est un comportement humain indiscutablement universel. Abondamment traité par la psychologie et les neurosciences, il demeure néanmoins le laissé-pour-compte de l’anthropologie. Si les connaissances empiriques accumulées à ce jour ont permis de bien le caractériser à des niveaux proximaux d’analyse, la question de son origine évolutionniste est, en contrepartie, souvent évacuée. Or, toute tentative sérieuse de comprendre ce comportement requiert une investigation de sa fonction adaptative et de sa phylogénèse. Le projet entrepris ici consiste en une analyse de cinq hypothèses ultimes sur le rire et l’humour, desquelles sont extraites des prédictions qui sont confrontées à des données empiriques provenant de disciplines diverses. En guise de conclusion, il est tenté de formuler un scénario évolutif qui concilie les différentes hypothèses abordées. / Laughter is a universal and ubiquitous human behavior. Widely investigated by psychology and neuroscience, it is still largely ignored by anthropology. While humor and laughter are well caracterised at proximate levels of explanation, the question of their evolutionary origins remains relatively unexplored. A number of recent hypotheses have yet attempted to shed light on the potential adaptive significance and phylogeny of these behaviors. This project consists of an analysis of five of these ultimate explanations, by confronting their predictions to empirical data from a large array of disciplines. In the end, I propose an evolutionary framework that synthesizes and reconciles these hypotheses.

Ontogenetic patterns in postcranial robusticity are analysed in the skeletons of eighty-two juvenile Later Stone Age hunter-gatherers with estimated ages at death ranging from infancy to late adolescence. Robusticity is quantified from cross-sectional geometric properties of diaphyses at sixteen sites throughout the skeleton, using radiography and casting methods. Skeletal growth profiles for strength measures are analysed with locally-weighted regression and additional curve fitting to evaluate developmental trajectories. Ethnographic accounts of infancy and childhood in modern Ju/'hoansi (Khoesan) communities provide a culturally-relevant interpretive framework for evaluating skeletal correlates of behaviour. This research demonstrates that bone strength properties can be functionally linked to behaviour among juveniles toward the reconstruction of patterns of physical activity among prehistoric children. Postcranial strength measures vary predictably with age such that developmental patterns and timing in appositional growth can be assessed reliably. The onset of walking among Later Stone Age juveniles is evident by two years of age from proportional lower to upper limb strength measures. The lower limb continues to adapt to increasing loading demands especially in response to torsional forces, and bending in the medio-lateral plane; biomechanical shape measures illustrate the gradual development of the femoral pilaster. Individual humeral strength is symmetrical with respect to the orientation maximal bending forces experienced throughout development, but the magnitude of the functional adaptive response is greater, on average, in the right limb with more than 70% of the sample over the age of six displaying right-side dominance. Humeral asymmetry and side dominance does not emerge until late childhood, and the majority of arm strength is accrued during adolescence, relative to the sex-combined mean values for Later Stone Age adults. Evidence for sexual dimorphism in upper limb properties is evident by late adolescence whereas sex-based patterns of mobility reflected in lower limb strength have yet to emerge. These results illustrate the developmental patterns that underlie postcranial markers of subsistence activities in Later Stone Age hunter-gatherers.

This thesis investigates changes in Iroquoian infant mortality and juvenile growth between 1250 and 1700 AD in the Lower Great Lakes region of North America. The objectives of this thesis are to investigate the tempo and quality of growth of Iroquoian infants and juveniles; to investigate the relationship between apparent neonatal and postneonatal mortality and predicted mortality ratios based on equal probability of mortality risk in the first year of life (1:11); and to investigate whether or not the ratio of neonatal to postneonatal mortality changed as a result of cultural change associated with the arrival of Europeans at around 1600 AD. These were investigated using a sample of infant and juvenile remains from twenty-one sites in upper New York state and Ontario. Tempo and quality of growth were examined by comparing femoral length at different ages to the Iroquoian adult femur length endpoint and to the growth patterns established in the Denver Growth Study and in other aboriginal North American archaeological samples. Above average infant growth is attributed to biocultural factors and infant mortality is largely caused by acute conditions. Below average juvenile growth, especially between two and seven years of age, is attributed to nutritional imbalances and overcrowding, poor sanitation, and infectious disease prevalence. Juveniles were likely chronically ill, resulting in poor attainment of stature, and this may have contributed to their deaths early in life. Apparent infant mortality was found to differ from predicted mortality, and this difference was attributed to cultural and environmental mortality biases that make interpretation difficult. Change in infant mortality ratios as a result of cultural change associated with European contact is evident in the Iroquoian context: the lack of neonatal remains in postcontact ossuaries is consistent with the ethnohistoric record, but the high proportion of neonates in precontact ossuaries suggests that observations made by ethnohistoric observers may not be applicable to our understanding of precontact burial patterns. The change in the ratio of neonatal to postneonatal remains in the pre- and postcontact periods is interpreted as evidence of changes in burial patterns rather than change in mortality risk.

Vitamin D plays a critical role in bone metabolism and many cellular and immunological processes, and low vitamin D levels have been associated with several chronic and infectious diseases. Previous studies have reported that many otherwise healthy adults of European ancestry living in Canada have low vitamin D concentrations during the wintertime. However, individuals of non-European ancestry are at a higher risk of having low vitamin D levels. This thesis examined vitamin D status in a sample of young adults of diverse ancestry living in the Greater Toronto Area. In my research I found that: 1) vitamin D levels (measured as 25(OH)D concentrations) are low in Canadian young adults, particularly in those of non-European ancestry; 2) vitamin D intakes, which were estimated to be on average higher than current Health Canada recommendations of 200 International Units (IU) per day, were inadequate to maintain optimal vitamin D levels year-round; 3) vitamin D levels undergo large seasonal changes. Winter 25(OH)D concentrations are substantially lower than those observed during the fall; 4) vitamin D intake is an important year-round predictor of 25(OH)D concentrations, but skin pigmentation and sun exposure are also important predictors during the times when UVB is adequate for cutaneous synthesis; and 5) vitamin D binding protein (VDBP) polymorphisms are significant predictors of 25(OH)D concentrations, but their effects vary by ancestry and season, indicating gene-environment interaction effects. My research shows that higher vitamin D intakes are needed to offset the seasonal drop in vitamin D levels and to ensure adequate vitamin D levels year-round for those at higher risk of insufficiency.

Ontogenetic patterns in postcranial robusticity are analysed in the skeletons of eighty-two juvenile Later Stone Age hunter-gatherers with estimated ages at death ranging from infancy to late adolescence. Robusticity is quantified from cross-sectional geometric properties of diaphyses at sixteen sites throughout the skeleton, using radiography and casting methods. Skeletal growth profiles for strength measures are analysed with locally-weighted regression and additional curve fitting to evaluate developmental trajectories. Ethnographic accounts of infancy and childhood in modern Ju/'hoansi (Khoesan) communities provide a culturally-relevant interpretive framework for evaluating skeletal correlates of behaviour. This research demonstrates that bone strength properties can be functionally linked to behaviour among juveniles toward the reconstruction of patterns of physical activity among prehistoric children. Postcranial strength measures vary predictably with age such that developmental patterns and timing in appositional growth can be assessed reliably. The onset of walking among Later Stone Age juveniles is evident by two years of age from proportional lower to upper limb strength measures. The lower limb continues to adapt to increasing loading demands especially in response to torsional forces, and bending in the medio-lateral plane; biomechanical shape measures illustrate the gradual development of the femoral pilaster. Individual humeral strength is symmetrical with respect to the orientation maximal bending forces experienced throughout development, but the magnitude of the functional adaptive response is greater, on average, in the right limb with more than 70% of the sample over the age of six displaying right-side dominance. Humeral asymmetry and side dominance does not emerge until late childhood, and the majority of arm strength is accrued during adolescence, relative to the sex-combined mean values for Later Stone Age adults. Evidence for sexual dimorphism in upper limb properties is evident by late adolescence whereas sex-based patterns of mobility reflected in lower limb strength have yet to emerge. These results illustrate the developmental patterns that underlie postcranial markers of subsistence activities in Later Stone Age hunter-gatherers.

This thesis investigates changes in Iroquoian infant mortality and juvenile growth between 1250 and 1700 AD in the Lower Great Lakes region of North America. The objectives of this thesis are to investigate the tempo and quality of growth of Iroquoian infants and juveniles; to investigate the relationship between apparent neonatal and postneonatal mortality and predicted mortality ratios based on equal probability of mortality risk in the first year of life (1:11); and to investigate whether or not the ratio of neonatal to postneonatal mortality changed as a result of cultural change associated with the arrival of Europeans at around 1600 AD. These were investigated using a sample of infant and juvenile remains from twenty-one sites in upper New York state and Ontario. Tempo and quality of growth were examined by comparing femoral length at different ages to the Iroquoian adult femur length endpoint and to the growth patterns established in the Denver Growth Study and in other aboriginal North American archaeological samples. Above average infant growth is attributed to biocultural factors and infant mortality is largely caused by acute conditions. Below average juvenile growth, especially between two and seven years of age, is attributed to nutritional imbalances and overcrowding, poor sanitation, and infectious disease prevalence. Juveniles were likely chronically ill, resulting in poor attainment of stature, and this may have contributed to their deaths early in life. Apparent infant mortality was found to differ from predicted mortality, and this difference was attributed to cultural and environmental mortality biases that make interpretation difficult. Change in infant mortality ratios as a result of cultural change associated with European contact is evident in the Iroquoian context: the lack of neonatal remains in postcontact ossuaries is consistent with the ethnohistoric record, but the high proportion of neonates in precontact ossuaries suggests that observations made by ethnohistoric observers may not be applicable to our understanding of precontact burial patterns. The change in the ratio of neonatal to postneonatal remains in the pre- and postcontact periods is interpreted as evidence of changes in burial patterns rather than change in mortality risk.

Vitamin D plays a critical role in bone metabolism and many cellular and immunological processes, and low vitamin D levels have been associated with several chronic and infectious diseases. Previous studies have reported that many otherwise healthy adults of European ancestry living in Canada have low vitamin D concentrations during the wintertime. However, individuals of non-European ancestry are at a higher risk of having low vitamin D levels. This thesis examined vitamin D status in a sample of young adults of diverse ancestry living in the Greater Toronto Area. In my research I found that: 1) vitamin D levels (measured as 25(OH)D concentrations) are low in Canadian young adults, particularly in those of non-European ancestry; 2) vitamin D intakes, which were estimated to be on average higher than current Health Canada recommendations of 200 International Units (IU) per day, were inadequate to maintain optimal vitamin D levels year-round; 3) vitamin D levels undergo large seasonal changes. Winter 25(OH)D concentrations are substantially lower than those observed during the fall; 4) vitamin D intake is an important year-round predictor of 25(OH)D concentrations, but skin pigmentation and sun exposure are also important predictors during the times when UVB is adequate for cutaneous synthesis; and 5) vitamin D binding protein (VDBP) polymorphisms are significant predictors of 25(OH)D concentrations, but their effects vary by ancestry and season, indicating gene-environment interaction effects. My research shows that higher vitamin D intakes are needed to offset the seasonal drop in vitamin D levels and to ensure adequate vitamin D levels year-round for those at higher risk of insufficiency.

The osteological paradox addresses how well interpretations of past population health generated from human skeletal remains reflect the health of the living population from which they were drawn. Selective mortality and hidden heterogeneity in frailty are particularly relevant when assessing childhood health in the past, as subadults are the most vulnerable group in a population and are therefore less likely to fully represent the health of those who survived. The ability of subadults to represent the health of those who survived is tested here by directly comparing interpretations of childhood stress based on non-survivors (subadults aged 6-20,14 females and 9 males) to those based on retrospective analyses of survivors (adults aged 21-46, 26 females and 27 males). Non-survivors and survivors were directly matched by birth year, using the Coimbra Identified Skeletal Collection; therefore interpretations of childhood stress reflect a shared childhood. Long bone and vertebral canal growth, linear enamel hypoplasia, cribra orbitalia, porotic hyperostosis, scurvy indicators and periosteal bone reactions were assessed for both groups. Overall, long bone growth generates the same interpretation of health for both non-survivors and survivors, and both groups exhibit the same range of stress (mild to severe), but the pattern of stress experienced in childhood differs between the two groups. Female survivors reveal different timing of stress episodes and a higher degree of stress than female non-survivors. Male survivors exhibit less stress than male non-survivors. These different patterns suggest that interpretations based solely on non-survivors would under-represent the stress experienced by female survivors and over-represent the stress experienced by male survivors, further demonstrating the importance of addressing issues of selective mortality. In addition, these different patterns suggest that hidden heterogeneity of frailty may be sex specific where males are more vulnerable to stress and females more able to develop resistance to stress and survive.

The osteological paradox addresses how well interpretations of past population health generated from human skeletal remains reflect the health of the living population from which they were drawn. Selective mortality and hidden heterogeneity in frailty are particularly relevant when assessing childhood health in the past, as subadults are the most vulnerable group in a population and are therefore less likely to fully represent the health of those who survived. The ability of subadults to represent the health of those who survived is tested here by directly comparing interpretations of childhood stress based on non-survivors (subadults aged 6-20,14 females and 9 males) to those based on retrospective analyses of survivors (adults aged 21-46, 26 females and 27 males). Non-survivors and survivors were directly matched by birth year, using the Coimbra Identified Skeletal Collection; therefore interpretations of childhood stress reflect a shared childhood. Long bone and vertebral canal growth, linear enamel hypoplasia, cribra orbitalia, porotic hyperostosis, scurvy indicators and periosteal bone reactions were assessed for both groups. Overall, long bone growth generates the same interpretation of health for both non-survivors and survivors, and both groups exhibit the same range of stress (mild to severe), but the pattern of stress experienced in childhood differs between the two groups. Female survivors reveal different timing of stress episodes and a higher degree of stress than female non-survivors. Male survivors exhibit less stress than male non-survivors. These different patterns suggest that interpretations based solely on non-survivors would under-represent the stress experienced by female survivors and over-represent the stress experienced by male survivors, further demonstrating the importance of addressing issues of selective mortality. In addition, these different patterns suggest that hidden heterogeneity of frailty may be sex specific where males are more vulnerable to stress and females more able to develop resistance to stress and survive.