Why did hunting weapon design change at Abri Pataud? Lithic use-wear data on armature use and hafting around 24,000–22,000 BP

Projectile technology is commonly viewed as a significant contributor to past human subsistence and, consequently, to our evolution. Due to the allegedly central role of projectile weapons in the food-getting strategies of Upper Palaeolithic people, typo-technological changes in the European lithic record have often been linked to supposed developments in hunting weaponry. Yet, relatively little reliable functional data is currently available that would aid the detailed reconstruction of past weapon designs. In this paper, we take a use-wear approach to the backed tool assemblages from the Recent and Final Gravettian layers (Levels 3 and 2) of Abri Pataud (Dordogne, France). Our use of strict projectile identification criteria relying on combinations of low and high magnification features and our critical view of the overlap between production and use-related fractures permitted us to confidently identify a large number of used armatures in both collections. By isolating lithic projectiles with the strongest evidence of impact and by recording wear attributes on them in detail, we could establish that the hunting equipment used during the Level 3 occupations involved both lithic weapon tips and composite points armed with lithic inserts. By contrast, the Level 2 assemblage reflects a heavy reliance on composite points in hunting reindeer and other game. Instead of an entirely new weapon design, the Level 2 collection therefore marks a shift in weapon preferences. Using recent faunal data, we discuss the significance of the observed diachronic change from the point of view of prey choice, seasonality, and social organisation of hunting activities. Our analysis shows that to understand their behavioural significance, typo-technological changes in the lithic record must be viewed in the light of functional data and detailed contextual information.

A Leaf Point Documents Hunting with Spears in the Middle Paleolithic at Hohle Fels, Germany

During the 2020 season at Hohle Fels Cave in the Ach Valley of southwestern Germany the excavation team from the University of Tübingen recovered a bifacial leaf point in archaeological horizon (AH) X. This horizon is the fifth deepest of the Middle Paleolithic horizons at the site and is located roughly 120 cm beneath the base of the rich Aurignacian layers of the cave. The new leaf point, or Blattspitze in German, is the first artifact of its kind found in situ in the Swabian caves since Gustav Riek’s excavation at Haldenstein Cave near the source of the Lone River recovered two leaf points in excellent preservation in 1936. The new find allowed our team to conduct the first techno-functional study of a freshly recovered leaf point from the European Middle Paleolithic. This study demonstrates that the leaf point was hafted at the less pointy end of the artifact. The leaf point bears clear damage to the pointed end of the artifact that occurred during a hunting episode. A Neanderthal knapper further damaged the tool during an attempt to resharpen and rejuvenate the tool. This damage was likely the reason the knapper discarded the leaf point at Hohle Fels. This result and a re-examination of the two leaf points from Haldenstein Cave indicate that late Neanderthals used Blattspitzen for hunting large game. The current results do not explicitly prove that spears with hafted leaf points were always thrown or used as thrusting spears, and one can easily imagine scenarios in which a weapon of this kind could be used in both ways. Ideally, the ongoing excavation at Hohle Fels will recover more leaf points, which will give us the opportunity to document the technological variability of this kind of tool with regard to their manufacture, function and life history. We also view the current research at Hohle Fels as an excellent opportunity to gain a better and more strongly contextualized understanding of the technological system linking lithic, botanical and osseous technologies during this phase of the Middle Paleolithic. This paper also considers the place that hafted leaf points have within the broader evolutionary development of hunting and projectile technology.

Natural Supercavitation Characteristic Simulation of Small-Caliber Projectile

Based on the multiphase model of FLUENT 6.3,a underwater projectile cavitation model is established for a new designed underwater projectile which have a disc cavitator.Then the cavitation number influence on cavitation form is concerned and contrast with the empirical formula of cavitation form.The conclusion is：with the increase of cavitation number,the drag coefficient will increase non-linear;the cavitation slenderness radio is greater,the drag coefficient is smaller. Supercavitation phenomenon is that when a object moves in water and it’s speed increases constantly, according to Bernoulli's equation, this will make the hydrostatic pressure that it bears drop. And when the pressure down to the vaporization pressure of water at that temperature, the surface moisture of the object will change into steam, form bubbles and wrap it. Due to the density of water and steam has magnitude deviation, the viscous resistance acting on the underwater moving object will reduce greatly, that can make the performance of underwater weapon enhance markedly. In the military applications, there are represented by Russia, the torpedo of “snowstorm” used the ventilation supercavitation theory and, represented by USA, the “20mm Supercavitation projectile” used the nature supercavitation theory. Facing the daily intelligentized contrail guided torpedo and mine, the small caliber supercavitation projectile technology has provided a new method for the short-range defense of surface vessel. As the nature supercavition projectile is a kind of uncontrolled, unpowered underwater weapon, the formation and stability of cavitation are more significative for performing the properties of projectile. The paper has done same simulate calculation for a new designed subcaliber supercavitation projectile, focused on the cavitation morphology and drag reduction ability under several different projectile velocity circumstance. This research can provide same basis for reasonable structure design of new projectiles.