Histomorphological species identification of tiny bone fragments from a Paleolithic site in the Northern Japanese Archipelago

Bone histomorphology is an effective method for species identification of fragmentary osseous remains. The 1997-1998 excavations of the Kashiwadai 1 Upper Paleolithic site (ca. 22-20.5 kyBP) in Hokkaido (the northern island of the Japanese Archipelago) yielded tiny bone fragments, which had been burned to white and broken into pieces less than 1 cm in size, making their species identification by gross morphology alone impossible. For the purpose of species identification, histomorphological analyses were performed on thin sections of the Kashiwadai 1 bone fragments. Compact bone cross sections taken from medium- to large-sized land mammals in the Pleistocene and Holocene Hokkaido were prepared for comparison. The structures of the Kashiwadai 1 samples consisted of secondary osteons and plexiform bone. Consideration of the presence versus absence of plexiform bone and quantitative assessments of osteon sizes and bone cortical thickness allows for distinction between medium-sized deer, large-sized artiodactyls, small- to medium-sized carnivores, large-sized carnivores, elephants, and humans. The histomorphological characteristics of the Kashiwadai 1 samples were quite similar to those of both sika deer and ancient sika deer. A probable conclusion is that medium-sized deer was the primary game hunted by Paleolithic people at the Kashiwadai 1 site. Interestingly, the samples did not include elephant or large-sized artiodactyls, which were the predominant species in other Paleolithic sites of the Japanese Archipelago. This is the first evidence of human hunting medium-sized animals in the Upper Paleolithic period of the Japanese Archipelago based on faunal remains.