The antlers of deer (Cervidae) are made of bone tissue and exhibit extraordinary toughness and energy absorption capability, necessary for combats for dominance during the rutting period. The work of fracture, corresponding to the area under the stress – strain curve, as an indicator of toughness is for antler about 9 MJ m-3 compared to about 0.3 - 2 MJ m-3 in long bones (Currey, Bones: Structure and Mechanics, Princeton University Press, 2002). In rare cases, antlers break during such combats. The breaking site, however, is never in the branching sites between main beam and side tines (see figure 1). The structural arrangements underlying such mechanical behavior are still unknown although many studies have investigated the mechanical behavior in the compact region of the antler main beam. In addition, deer antlers stand apart from other vertebrate biomineralized organs in that they are regenerated in toto annually and with a startling growth rate. Although they are grown over an extremely short period of time (4-5 months), they can attain elaborate branched or palmate forms, huge sizes (>1.0m), and weights of several kilos. Less is known about the microstructural arrangements important to such rapid and large-scale tissue growth and organization especially in the branching region.

The aim of this project is therefore to characterize the relations between structure and mechanical behavior on different length scales during antler bone growth especially in the branching sites of deer antler. In addition, structural principles, affecting the mechanical behavior of branching points, will be applied to 3D printed construction parts.