The Young's Modulus and Impact Energy Absorption of Wet and Dry Deer Cortical Bone

Abstract

We have shown recently that antlers of red deer, at the time that they are used in fights in the rut, are essentially dry. We have also shown that dry antler material has a lower impact energy absorption than that of wet antler, a property which, in a fight, is probably very important in the first clashing of antlers. However, dry antler has a much higher Young's modulus (stiffness) than wet antler, and this property will be important in the pushing match that follows the initial impact. These values were compared with those of wet bone, and it was found that although dry antler had a somewhat lower Young's modulus than wet bone, it had a much higher impact energy absorption. In that paper we did not consider the properties of dry bone. We now rectify that. The present paper compares the Young's modulus and impact energy absorption of wet and dry antler with that of wet and dry long bone of deer. It is found that the Young's modulus of dry antler is slightly less (12%) than that of wet long bone, which is in turn slightly less (7%) than that of dry long bone. On the other hand the impact energy absorption of dry antler is much (x6.6) greater than that of wet bone and even greater (x14.3) than that of dry bone. (The impact energy absorption of wet antler could not be measured consistently; it was certainly very high). We suggest that the material properties of antler (which is necessarily dry when used in fights) are superior to those of dry long bone material because, although they have somewhat lower (18%) Young's modulus, they have a much greater (x14) impact energy absorption. The properties of wet long bone and wet antler material are given for comparison, but neither could be used in reality.