From Biped to Strider: The Emergence of Modern Human Walking, Running, and Resource Transport: D. Jeffrey Meldrum and Charles E. Hilton, eds. Kluwer Academic/Plenum Publishers, New York 2006. ISBN 0-306-48000-X, $44.00, pp. 213

Hum Ecol (2006) 34:731734

DOI 10.1007/s10745-006-9043-z

BOOK REVIEW

From Biped to Strider: The Emergence of Modern Human Walking, Running, and Resource Transport

D. Jeffrey Meldrum and Charles E. Hilton, eds. Kluwer Academic/Plenum Publishers, New York 2006. ISBN 0-306-48000-X, $44.00, pp. 213

Philip L. Reno

Published online: 20 July 2006 # Springer Science+Business Media, Inc. 2006

This edited volume reports a symposium held at the 2000 meeting of the American Association of Physical Anthropologists. The editors main premise is that the evolution of human locomotion marked a transition from merely obligate bipedal australopithecines to efficient endurance striders. They suggest that many anthropologists fail to acknowledge the specialized running capabilities of humans (I admit to being one). However, they also recognize that bipedal locomotion has significant implications for resource transport. Thus, the aim of this volume is to present a variety of analytical approaches that reveal how human bipedality facilitates and limits patterns of landscape use, mobility, and resource collection. The book consists of two very distinct parts. The first explores the nature of pre-Homo bipedality, with a particular focus on the morphology of the australopithecine foot. The second addresses various issues concerning behavioral and ecological implications of bipedal locomotion for the genus Homo.

The highpoint of the first section is Beguns investigation into the ancestral locomotor behavior from which hominid bipedality evolved. Presenting a detailed functional analysis, he argues that phylogenetic parsimony dictates that the last common chimp-human ancestor was a knuckle-walker largely in the mode of living African apes. Particularly intriguing is Beguns demonstration of a number of characters that evolved in parallel in the wrists of apes and the extinct knuckle-walking perissodactyl, Macrotherium. Importantly, given the diversity of the intended audience, his clearly stated hypotheses and illustrations make potentially complex anatomical analysis accessible to the non-morphologist.

Also of interest is Schmids report on the Laetoli footprints in Tanzania. Having served as a member of the team commissioned to assess their preservation in 1995, Schmid admits to initial puzzlement concerning the extreme similarity of the footprints to those of modern humans in preserving a stable longitudinal arch and lacking of any indication of an abducted big toe. However, he focuses on the deep impressions left by the lateral ball of the foot, which suggest to him that australopithecines practiced a distinct mode of weight

P. L. Reno (*)

Biological Anthropology Program, School of Biomedical Sciences, Kent State University, Kent, OH, USAe-mail: [email protected]

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transfer that reflected incompetent hip abductors and an ape-like trunk, which precluded arm swinging during walking. However, it should be noted that this interpretation runs counter to other recent analyses (Lovejoy et al., 2002; Lovejoy, 2005a, b).

Kramer steps back from morphology to address the behavioral ecology of hominid locomotion, providing a valuable discussion of efficiency. In contrast to anthropological convention, she defines multiple parameters beyond caloric expenditure, such as water budgets, range use, and fatigue and injury protection, formulating a broader, more holistic concept (and one much more likely to reflect real fitness). To explore the role of object transport in hominid evolution, she models the effects of burdens on energetic costs in modern humans and female australopithecines (i.e., Lucy). Her results suggest that australopithecines experienced a more rapid rise in cost of transport with increased load than do modern humans. Thus, Kramer concludes that female australopithecines were adapted to slow speed foraging requiring only limited burden carrying. While an intriguing hypothesis, her analysis did not include examination of the effects of increased burden load relative to individual body mass (and not increments of absolute mass), as the biological benefits of a load (i.e., food resources and dependent young) would appear to also scale with body size.

Deloison presents a distinctly atomistic and adaptationist description of recently discovered foot fossils from Sterkfontein. Without providing adequate functional context or any indication of intraspecific variation, she simply categorizes traits as being either arboreal chimpanzee-like or terrestrial human-like. Thus, it is unclear whether features are chimp-like because australopithecines were approximately chimp-sized or if they actually shared the proposed locomotor adaptations. Figure quality (many are out of focus) and a lack of comparative specimens make her arguments difficult to interpret, especially for readers not acquainted with these fossils. In addition, no figure is provided to illustrate her claim that the hallucial surface of the medial cuneiform allowed for significant abduction of the great toe.

Rounding out the first section are two additional morphological analyses of the foot. Meldrum compares the Laetoli footprints to those made by recent Hawaiians and presents a very different interpretation than does Schmid (as well as much of the relevant literature). In contrast to Hawaiian prints, Meldrum detects indications of a tapered heel, lack of a ball, and significant great toe abduction at Laetoli. Berillon presents an architectural analysis of the hominoid foot, which he defines as a quantification of joint angulation in neutral position. He concludes that australopithecines lacked a stable longitudinal arch and could produce modest great toe abduction. However, his functional interpretations should be taken cautiously, as nearly all relevant values for australopithecines fall within the range of his modern human sample.

Gruss and Schmitt shift the focus away from australopithecines by using basic biomechanical principles to hypothesize that the relatively long tibia seen in the Nariokotome H. erectus skeleton (KNM WT-15000) would increase bending forces on the leg. However, when the walking kinematics of people with various tibia-femur proportions was actually measured, no differences in bending forces were detected. Thus they conclude that individual behavioral mechanisms, such as adjusting the pressure center at the foot during the stride, could counteract the variations in morphology. This study underscores the different effects that phenotypic variation can have on idealized biomechanical models compared to actual performance at the organismal level.

Inspired by the striking differences between pit bulls and greyhounds, Carrier proposes that the short and stout bodies of australopithecines were the result of selection for fighting, and that the ability to manufacture weapons allowed humans to evolve sleek bodies adapted for endurance running. In building his case for australopithecine fighting ability, Carrier is careful to isolate locomotor from fighting adaptations; however, in some cases he overlooks

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the locomotor benefits of purported fighting features. For example, the wide pelvis of Lucy is argued to be a hindrance to locomotion and instead serves to increase postural stability during aggressive conflicts. However, the biomechanical properties of the hip joint and musculature can be calculated for Lucy and have been shown to fall within the modern human range (Lovejoy, 2005b). In addition, while the analogy to canids (dogs) is alluring, Carriers scenario needs to account for reduced hominid male canines (Brunet et al., 2002), which are universally used as aggressive displays and/or weapons by both Old World monkeys and apes, and contrast starkly with many Miocene hominoids that evince very large canines.

The last two analyses address the interrelationship between resource collection and physical activity in modern humans. Hilton and Greaves report on the roles that sex, age and seasonality play in determining day-range and burden load in traditional Venezuelan foragers. Counterintuitively, females, and particularly older individuals, transport the heaviest loads in an effort to maximize resource collection per trip. In addition, the variation reported in seasonal and sex-specific effort invested into resource collection indicates the relationship between economic activity and mechanical loading is likely to be complex when generally applied to foraging peoples.

Following the premise that cortical bone distribution reflects loading history, Ogilvie infers a reduction in mobility associated with the transition from foraging to farming in American Southwest archaeological populations, based on decreased femoral cross-sectional area in agricultural societies. While a common analytical approach, recent studies have questioned a simple correlation between bone shape and loading history (Bertram and Swartz, 1991; Pearson and Lieberman, 2004). In addition, it is not intuitively obvious that activity levels should be significantly reduced in agriculturalists compared to foragers. Ogilvie is careful to document significant dietary shifts associated with this economic transition; however, this may imply that relying on loading may obscure potential influences on skeletal morphology other than activity level.

From Biped to Strider has a promising goal to explore the interactions among human bipedality, mobility, resource transport, and ecology. This is best accomplished in the second half of the book, which is likely to be of greater interest to the readership of Human Ecology (however, missing is any discussion of the impact of brain size on pelvic form during the Pleistocene). The first half largely fails in its promise to provide an expanded perspective on the implications of bipedality for human evolution. With the exception of Kramers piece, only morphology-based analyses of early hominid locomotion are presented, and most are merely concerned with the relative competence of australopithecine bipedality. This lack of diversity presented in what the editors acknowledge is a contentious field serves to bolster what may be nonrepresentative support for the initial premise of this volume (that hominid evolution marks the transition from a merely an obligate biped to a modern efficient strider). This volume therefore misses an opportunity to consider similar interesting questions concerning landscape use and resource transport during the australopithecine phase of hominid evolution, which would have been of considerable interest to the wider anthropological community.

References

Bertram, J. E., and Swartz, S. M. (1991). The Law of Bone Transformation: A case of crying Wolff?Biological Reviews 66: 245273.

Brunet, M., Guy, F., Pilbeam, D., Mackaye, H. T., Likius, A., Ahounta, D., Beauvilain, A., Blondel, C., Bocherens, H., Boisserie, J. R., De Bonis, L., Coppens, Y., Dejax, J., Denys, C., Duringer, P.,

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Eisenmann, V., Fanone, G., Fronty, P., Geraads, D., Lehmann, T., Lihoreau, F., Louchart, A., Mahamat,A., Merceron, G., Mouchelin, G., Otero, O., Pelaez, C. P., Ponce, D. L., Rage, J. C., Sapanet, M., Schuster, M., Sudre, J., Tassy, P., Valentin, X., Vignaud, P., Viriot, L., Zazzo, A., and Zollikofer, C. (2002). A new hominid from the upper miocene of chad, Central Africa. Nature 418: 145151. Lovejoy, C. O. (2005a). The natural history of human gait and posture. Part 2. Hip and thigh. Gait Posture

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Lovejoy, C. O. (2005b). The natural history of human gait and posture. Part 1. Spine and pelvis. Gait Posture21: 95l12.

Lovejoy, C. O., Meindl, R. S., Ohman, J. C., Heiple, K. G., and White, T. D. (2002). Maka Femur and its bearing on the antiquity of human walking: Applying contemporary concepts of morphogenesis to the Human Fossil Record. American Journal of Physical Anthropology 119: 97133.

Pearson, O. M., and Lieberman, D. E. (2004). The aging of Wolffs law: Ontogeny and responses to mechanical loading in cortical bone. American Journal of Physical Anthropology Supplementary 39: 6399.