Wound ballistics: The prey specific implications of penetrating trauma injuries from osseous, flaked stone, and composite inset microblade projectiles during the Pleistocene/Holocene transition, Alaska U.S.A.
Graphical abstract
Introduction
Clues to a killer's motive are often found in the cause of death. For penetrating trauma injuries, forensic scientists rely on the study of wound ballistics to help determine the net effect of the lethal weapon used that ultimately lead to the victim's demise. In essence, these scientists reconstruct the crime scene – much like archaeologists do when excavating a site. In general, archaeological investigations to date conclude that projectile points made from bone and stone were both consistent yet discrete aspects of hominid technological evolution until the Upper Paleolithic and the dawn of composite microblade technology. This new point class merged the best attributes from both materials; the strength and durability of bone and the lethal cutting edge from flaked stone (Elston and Brantingham, 2002). The net effect or lethality of prehistoric projectile points has been a common theme for replication experiments conducted to gain insights that go beyond what the artifactual evidence can provide.
Improved understanding of the performance attributes of projectiles recovered from archaeological contexts is of considerable interest to any anthropologist of human technological practice. Technological analyses inform, for example, on evolving hominid cognitive capacities (Ambrose, 2001; de Beaune, 2004, Shea, 2006, Stout et al., 2008), the behavioral ecology and economic strategies of human foragers (Kelly, 1988, Kuhn, 1994a, Surovell, 2012, Torrence, 1989), the pattern and process of technological evolution (Bettinger and Eerkens, 1999, Eerkens and Lipo, 2007, O'Brien et al., 2014; Shennan, ed., 2009), and culture historical interpretations made about past archaeological sequences (Davis and Knecht, 2010). This paper seeks to add to this domain through the experimental examination of differences in performance characteristics between three projectile point classes known to have been used in the terminal Pleistocene by Alaskan hunters. These classes, bone, stone and composite point forms, stand to represent three of the most distinctive point technologies used by hunters prior to the advent of iron armatures. As such we seek to provide information to benefit interpretations of the early Alaskan archaeological record, while providing insights of more general applicability for the anthropology of hunting technology.
High latitude hunters-gatherers during the Upper Paleolithic developed an osseous tool industry dominated by a variety of projectile point forms utilizing small lithic tool combinations often embedded in ivory, bone, or antler projectiles. Composite microblade technology became common in the Late Pleistocene Arctic regions of Northeast Asia then expanded east to Alaska by the Pleistocene/Holocene transition (Hoffecker and Elias, 2007).
The microblade tradition in interior Alaska derives from this Northeast Asian microlithic development. It has been labelled the Denali Complex and linked to the eastern Siberian Dyuktai culture (Hoffecker and Elias, 2007, West, 1996). These linked traditions are characterized by use of a distinctive wedge-shaped microcore, production of small and finely crafted microblades, and use of burin tools presumably for shaping slotted osseous pieces for microblade insets among other tasks (West, 1967, West, 1996 and contributions in West, ed., 1996). Although composite projectile points with inset microblades have yet to be recovered from interior Alaska sites, they have been recovered from the 8000 year old Zhokhov site north of Siberia (Pitul’ko, 2001, Pitul’ko and Kasparov, 1996) and regionally, seven slotted antler points were found in association with four microblades at the Trail Creek Caves archaeological site near Seward Peninsula, Alaska (Larsen, 1968). To the southwest, a single slotted point was retrieved from Lime Hills Cave, Alaska (Ackerman, 1996), and one specimen was recovered from the Gladstone Ice-patch in southwestern Canada (Helwig et al., 2008). For these reasons and proximities, it is widely believed that the microblades deposited in the Alaskan interior were manufactured as part of composite point technology (Holmes, 2011).
In close association with Denali is the Nenana Complex defined by the use of teardrop and/or triangular shaped, bifacially flaked projectile points, known as Chindadn points (Bever, 2001, Cook, 1996, Goebel et al., 1991, Holmes, 2011, Pearson, 1999). A third projectile variety—consisting of simple, unslotted bone/antler/ivory points—has been found in dated contexts with both Denali and Nenana assigned cultural components (Bowers and Reuther, 2008, Holmes, 1996, Potter, 2007, Yesner et al., 2000) and makes up the third class of point we consider in this investigation. This technology has not been attributed to any single early Alaskan cultural tradition or complex, and we assume it was a universal option available to any hunter-gatherers since hominids developed the ability to sharpen bone and haft it to a shaft.
Microblade and Chindadn point-bearing assemblages occur in the same region of Alaska (especially Central Alaska Range and Tanana Valley) in sites of roughly the same age, but they are rarely found in the same archaeological components. For this reason, some see Nenana as a distinct and unrelated cultural tradition from Denali, perhaps tied to Paleoindian migrations to southern North and South America (Hoffecker and Elias, 2007). In contrast, other archaeologists suggest that microblade tools and small (teardrop or triangular) lithic bifaces could have been parts of functionally distinct toolkits used by the same people, perhaps for different seasonal activities or as a result of shifting adaptations to habitat changes (Holmes, 1996, Holmes, 2011, Potter, 2011, West, 1996). Microblades discovered in association with bifacial points in a few site components near the Tanana River lend some credence to the latter interpretation (Holmes, 2011). Other studies evaluate the relationship between land use strategies and site elevation for explaining technological variability (Potter, 2011, Wygal, 2016).
For Chindadn and composite inset microblade points to have been used by the same people but deposited in mostly separate assemblages, these point classes must have been used in highly specialized and non-overlapping tool kits by foragers targeting different game, in different habitats or seasons. Point selection for a specific hunting target or context should be sensitive to the relative effectiveness of the points in the hunt (Torrence, 1983), and it follows that if the point types were used by the same people for different purposes then they should have distinctive functional qualities. A key element of effectiveness should be a projectile point's overall wounding potential, which may differ depending on shot placement and the anatomy of the target prey. If the availability of different prey was segregated in space or time—seasonally or as a result of longer-term changes in ecology—then point technologies related to hunting forays would end up segregated in task specific archaeological assemblages.
In this study, we explore the differences in performance of the composite inset microblade, flaked stone, and simple bone point classes. We do this with an analysis of the wound potential of the different point classes based on two ballistic experiments designed to see how penetration and shot placement varied by material and tissue density. The first experiment evaluates the Total Wound Area (TWA) using penetration and tip-metrics of each point class when shot into ballistic gelatin. The second experiment considers penetration depth, TWA, durability, and lethality created by points launched into an animal carcass (reindeer). With this dual experimental design, we explore the possibility that performance advantages may shift between technological complexes (composite microblade points, bifacial lithic points and simple sharpened-tip bone points) as a result of technological needs relating to wounding potential and prey anatomy. As such, we provide a novel perspective on hunter-gatherer behavior and lithic tool variability. The results argue for the broader inclusion of wound ballistics in archaeological middle range theory of hunting tool kits.
Section snippets
Background
Although the inspiration for our research comes from a specific question about technological variability from interior Alaskan archaeological sites during the Pleistocene/Holocene transition, here we seek to establish a larger frame of reference for questions concerning wound ballistics and archaeological experimentation.
Materials and methods
Based on an initial pilot study we conducted in 2013 (online supplementary material - Pilot Study, S1), our research design included both laboratory and field ballistic experiments on the three projectile point classes discussed above. Simple conically shaped bone points, bifacially flaked obsidian stone points, and composite slotted inset microblade antler points were designed to replicate alternate technologies (Nenana and Denali) inferred for the Paleo-Arctic Tradition in the interior of
Laboratory experiment 1: ballistic gelatin
Ballistic gelatin is a frequently used medium in experiments to study the effects of high-velocity projectile penetration into a uniform substance (Swain et al., 2014). While the approach does not replicate penetration dynamics in heterogeneous (animal) targets, ballistic gel experiments are effective in assessing the morphological differences created in the wound channel due to differences in the morphology of projectiles themselves as opposed to the interference of animal structures (online
Field experiment: Reindeer
To further explore the relative wounding profile and performance characteristics of the three point classes, the first author set up a second experiment using a reindeer carcass to explore aspects of the performance characteristics of the three different projectile classes. On December 14, 2016 with ambient temperatures at −26 °C, the first author experimented on a freshly culled reindeer carcass from a local farm in Fairbanks, Alaska. The carcass was complete (not subject to any post mortem
Discussion
Based on these experiments, we can begin to identify a range of options and trade-offs available to prehistoric hunters when choosing a projectile technology. Plain bone points have the narrowest tip angles with no cutting edge. As a result they create puncture type wounds that are more likely to get past the dense backbone, but inflict more limited internal wounds and have less potential for blood loss. Wider projectiles that slice, such as the bifacially flaked point used in this experiment
Conclusion
In this study we examined the wounding dynamics of three prehistoric projectile point forms used in interior Alaska at the Pleistocene/Holocene transition. The results of two experiments—one using ballistic gelatin and one targeting a fresh reindeer carcass—identify trade-offs in wound performance of different point classes. The differences observed may help us understand changes in projectile use over several thousand years in the early settlement of the Alaskan interior. Our study, based on
Acknowledgments
The authors would like to thank those who have offered their encouragement and critique including; John Shea, Jean-Marc Pétillon, Christopher Ellis, Jon Erlandson, Quentin Mackie, Chuck Holmes, Jeffrey Rasic, Holly McKinney, John Dockall, Roeland Paardekooper, Morten Kutschera, Vittorio Brizzi, Patrick O'Grady, Michael Rondeau, Leland Gilsen, Jenn Huff, Jon Krier, Alaska Fish and Wildlife, Bureau of Land Management (Oregon, USA), and the University of Washington. A special thanks to George
References (84)
- et al.
Developing a stable point: evaluating the temporal and geographic consistency of Late Prehistoric unnotched triangular point functional design in Midwestern North America
J. Anthropol. Archaeol.
(2017) - et al.
Shanidar 3 Neandertal rib puncture wound and paleolithic weaponry
J. Hum. Evol.
(2009) - et al.
Asphaltum hafting and projectile point durability: an experimental comparison of three hafting methods
J. Archaeol. Sci.
(2012) Finding the Paleoindian spearthrower: quantitative evidence for mechanically-assisted propulsion of lithic armatures during the North American Paleoindian period
J. Archaeol. Sci.
(2015)- et al.
Projectile impact fractures and launching mechanisms: results of a controlled ballistic experiment using replica Levallois points
J. Archaeol. Sci.
(2014) - et al.
Hunting lesions caused by osseous projectile points: experimental results and archaeological implications
J. Archaeol. Sci.
(2008) - et al.
Hunting with Howiesons Poort segments: pilot experimental study and the functional interpretation of archaeological tools
J. Archaeol. Sci.
(2008) - et al.
Evidence from the Yana Palaeolithic site, Arctic Siberia, yields clues to the riddle of mammoth hunting
J. Archaeol. Sci.
(2013) - et al.
Innovation and cultural transmission in the American Paleolithic: phylogenetic analysis of eastern Paleoindian projectile-point classes
J. Anthropol. Archaeol.
(2014) - et al.
Penetrating thoracic trauma in arrow injuries
Ann. Thorac. Surg.
(2001)