Bone modification in the Arctic National Wildlife Refuge, Alaska (2010)

Skeletal bones and antlers from past generations of wildlife are frequently found and consumed by other animals, living out a second life as an important dietary resource. Such gnawing may leave characteristic modifications, including tooth marks, providing physical evidence of a behavior and nutrient resource that is often challenging to directly observe and quantify. Documenting and interpreting features of bone modification can fill knowledge gaps regarding species’ behavioral ecology, nutrient requirements, and interactions in modern ecosystems, as well as in historical, archeological, and paleontological contexts. While prior research has documented characteristic patterns of bone modification and gnawing for a variety of bone consumers, these studies generally focus on a single species or taxonomic group, with only limited comparison to bone modifications generated by co-occurring groups (i.e., ruminants vs. carnivorans vs. rodents). Cataloguing bone modifications at ecosystem-scales has rarely been the focus of past work, which may be partially responsible for a profound gap in existing knowledge regarding how co-occurring and competing bone consumers partition this shared source of nutrients (e.g., calcium, phosphorous, and calorie-rich marrow). We compiled available literature on bone modifications made by rodents, ungulates (specifically ruminants), and carnivorans. Using this compilation as a starting point, we characterized the full suite of modifications observed on shed antlers and skeletal bones collected during standardized bone surveys along the Coastal Plain of the Arctic National Wildlife Refuge (Alaska). In total, we described, summarized, and photographed 27 distinct classes of pits, punctures, scores, furrows and fractures, and, when possible, identified the taxonomic group that is known or likely responsible for each modification class. Seven of these classes, all attributed to ruminants (likely caribou), have not been previously described. This dataset includes every occurrence of the 27 modification classes observed on the 1,567 antlers and 224 skeletal bones collected from the Arctic National Wildlife Refuge. A unique strength of this dataset is that it includes the largest assessment of bone modifications on a single skeletal element (antlers), providing unparalleled opportunities to evaluate variability in bone modification across space (~200 kilometers) and through time (antlers can persist on tundra surfaces for hundreds to thousands of years). Detailed descriptions, images, and explanations of the most likely bone modifier (ruminant, rodent, carnivoran) associated with each of the modification classes can be found within Gaetano M, Miller J, Wald EJ, Druckenmiller P. in press The Atlas of Arctic bone modification. Ecol. Arch.

过往野生动物的骨骼与鹿角常被其他动物发现并取食，作为重要的膳食资源实现“二次生命”。这类啃食行为会留下具有标志性的改造痕迹，包括齿痕，为这类通常难以直接观测与量化的行为与营养资源提供了实物佐证。对骨骼改造特征进行记录与解读，能够填补我们在物种行为生态学、营养需求，以及现代生态系统、历史、考古与古生物学背景下的物种交互相关的知识空白。尽管此前已有研究针对多种骨骼取食动物记录了骨骼改造与啃食的典型模式，但这些研究通常仅聚焦单一物种或类群，仅极少对比共存类群（即反刍动物（ruminants）、食肉动物（carnivorans）与啮齿类（rodents））所造成的骨骼改造痕迹差异。以生态系统尺度对骨骼改造特征进行编目，在过往研究中极少成为核心主题，这或许是当前学界在共存且竞争的骨骼取食动物如何分配这类共享营养资源（如钙、磷与高热量骨髓）方面存在显著知识缺口的部分原因。我们整理了关于啮齿类（rodents）、有蹄类（ungulates）（具体为反刍动物（ruminants））与食肉动物（carnivorans）造成的骨骼改造痕迹的现有文献。以此汇编为基础，我们对在北极国家野生动物保护区（Arctic National Wildlife Refuge，阿拉斯加（Alaska））沿海平原开展的标准化骨骼调查中采集到的脱落鹿角（shed antlers）与骨骼上观察到的全部改造特征进行了表征。共计，我们对27种不同类型的凹坑、穿刺痕迹、刻痕、沟槽与骨折特征进行了描述、汇总与拍照，并在可行的情况下，确定了已知或疑似造成每一类改造痕迹的分类类群。其中7类改造痕迹均归因于反刍动物（ruminants，大概率为驯鹿（caribou）），此前从未被报道过。本数据集包含了在北极国家野生动物保护区（Arctic National Wildlife Refuge）采集到的1567件鹿角与224件骨骼上出现的全部27类改造痕迹。本数据集的独特优势在于，它包含了针对单一类骨骼结构（鹿角）的最大规模骨骼改造评估，为评估空间（约200公里范围）与时间（鹿角可在苔原（tundra）表面留存数百至数千年）维度下的骨骼改造变异性提供了前所未有的契机。关于每一类改造痕迹对应的最可能的骨骼取食类群（反刍动物（ruminants）、啮齿类（rodents）、食肉动物（carnivorans））的详细描述、图像与解释，可参阅Gaetano M、Miller J、Wald EJ、Druckenmiller P待刊的《北极骨骼改造图集（The Atlas of Arctic bone modification）》，该文将发表于Ecol. Arch.。