Libby W. Cowgill

Developmental Variation in Ecogeographic Body Proportions

While ecogeographic variation in adult human body proportions has been extensively explored, relatively less attention has been paid to the effect of Bergmanns and Allens rules on human body shape during growth. The relationship between climate and immature body form is particularly important, as immature mortality is high, mechanisms of thermoregulation differ between young and mature humans, and immature body proportions fluctuate due to basic parameters of growth. This study explores changes in immature ecogeographic body proportions via analyses of anthropometric data from children included in Eveleth and Tanners (1976) Worldwide Variation in Human Growth, as well as limb proportion measurements in eight different skeletal samples. Moderate to strong correlations exist between climatic data and immature stature, weight, BMI, and bi-iliac breadth; these relationships are as strong, if not stronger, in immature individuals as they are in adults. Correlations between climate and trunk height relative to stature are weak or nonexistent. Altitude also has significant effects on immature body form, with children from higher altitudes displaying smaller statures and lower body weights. Brachial and crural indices remain constant over the course of growth and display consistent, moderate correlations with latitude across ontogeny that are just as high as those detected in adults. The results of this study suggest that while some features of immature body form, such as bi-iliac breadth and intralimb indices, are strongly dictated by ecogeographic principles, other characteristics of immature body proportions are influenced by intrinsic and extrinsic factors such as nutrition and basic constraints of growth.

The Foragers of Point Hope: The Biology and Archaeology of Humans on the Edge of the Alaskan Arctic

On the edge of the Arctic Ocean, above the Arctic Circle, the prehistoric settlements at Point Hope, Alaska, represent a truly remarkable accomplishment in human biological and cultural adaptations. Presenting a set of anthropological analyses on the human skeletal remains and cultural material from the Ipiutak and Tigara archaeological sites, The Foragers of Point Hope sheds new light on the excavations from 1939 to 1941, which provided one of the largest sets of combined biological and cultural materials of northern latitude peoples in the world. A range of material items indicated successful human foraging strategies in this harsh Arctic environment. They also yielded enigmatic artifacts indicative of complex human cultural life filled with dense ritual and artistic expression. These remnants of past human activity contribute to a crucial understanding of past foraging lifeways and offer important insights into the human condition at the extreme edges of the globe.

Femoral Diaphyseal Shape and Mobility: An Ontogenetic Perspective

The ratio of midshaft femoral anteroposterior (I x ) to mediolateral (I y ) second moments of area has been suggested as a possible indicator of mobility, and has been applied as an analytic tool to paleoanthropological and archaeological samples with variable success. Under this model, biomechanical loads associated with increased mobility modify the shape of the femoral midshaft from a roughly circular cross section to an anteroposteriorly reinforced one. While previous research indicates that immature femora respond to changes in the manner of locomotor loading (Ruff 2003; Cowgill et al. 2010), relatively fewer studies have examined population-level differences in immature femoral shape as a product of overall group mobility.

Introduction: Humans on the edge of the Alaskan Arctic

The ability to make a living in the Arctic represents one of humanity’s truly exceptional achievements. The fact that it was accomplished by people who depended exclusively on wild (that is, uncultivated) resources attests to the levels of human imagination and ingenuity in creating cultural systems that effectively buffered against the physical elements of the Arctic. For these reasons, studies of North American Arctic foraging peoples have long played an important role in the early foundations and development of American anthropology (Collins, 1984; Dumond, 1987; Burch, 1988). North American Arctic foragers represent one end of the range of variation of the human foraging spectrum (Bettinger, 1991; Kelly, 1995; Binford, 2001), but, as they exist at one end of that range, they especially present insight into human adaptability. Arctic peoples clearly push the boundaries of human adaptation and resiliency by living in areas marked by long periods of cold temperatures, limited availability of plant resources for food, and marked seasonal variation in daylight hours. North American Arctic foragers, both today and in the past, present a broad range of sophisticated technology, dietary flexibility, social organization, and residential mobility as they expanded across large areas of the North American Arctic landscapes. Given this remarkable resiliency in the face of adverse conditions, researchers have examined numerous aspects of cultural and biological characteristics of North American Arctic foragers in order to understand the complex problems related to survival in these circumpolar environments, and the many solutions taken by humans to overcome them. As separate cultural entities, Arctic forager groups often possess distinctive organizational strategies and technological skills that provide an impressive array of innovative solutions for survival in their circumpolar landscapes

Femoral neck-shaft angle and climate-induced body proportions

OBJECTIVES Declination in femoral neck-shaft angle (NSA) is commonly linked to an increased level of physical activity during life. More recently, however, research suggests that lower NSA might also be explained, in part, as the mechanical consequence of differences in ecogeographic body proportions. This study tests the proposed link between NSA and climatic-induced body proportions, using relative body mass (RBM), throughout the course of development. MATERIALS AND METHODS NSA and RBM were collected for 445 immature remains from five geographic locations. NSA and RBM were standardized for age-effects. ANOVA was used to examine when population differences emerged in both NSA and RBM. Regression analyses were used to examine the pattern of relationship between NSA and RBM. RESULTS Populations differ significantly in NSA and RBM before skeletal maturity, and these differences occur early in life. While both NSA and RBM change over the course of development, no significant relationship was found between NSA and RBM for any sample, or any age category (p = .244). DISCUSSION Individuals who have relatively greater relative body mass do not necessarily have lower NSA. Population differences in NSA were found to be variable, while differences in RBM remained consistent across the developmental span. Taken together, these results suggest that regardless of body proportions, the degree of declination of NSA is presumed to be similar among individuals with similar gait and ambulatory behaviors. Conversely, populations differ in RBM from birth, and these differences are consistent throughout development. These two measures likely are responsive to diffing stimuli, and any potential relationship is likely complex and multifactorial.