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Field Specialists out in the field

PRELIMINARY RESULTS FROM FORENSIC STUDIES ON THE 6.5-MILE SKELETON

Forensic Specialist Kassie Sugimoto conducted a Skeletal Studies class in November 2015, at SRScorp, the offices and archaeological laboratory of Dr. Nancy Anastasia Wiley, Haines, Alaska. The class included about 30 hours of lecture and hands-on instruction with human skeletal remains and was attended by 10-20 local residents. Forensic anthropology is the applied branch of physical anthropology that attempts to identify skeletonized human remains for legal purposes. Forensics uses methods gleaned from the hard sciences to assess age, sex, ancestry, stature, and the lifestyle of an unknown individual. The application of the scientific method and statistical models in forensic methods has created the ability to scientifically test hypotheses and produce reliable results that can be verified through duplicate testing. Forensic methods such as osteometrics (skeletal measurements) and non-metric analyses (the analysis of heritable characteristics) can also be used to study the lifeways (such as diet, disease, demography, gene flow, physical activity, and trauma) of past populations. Sugimoto used forensic and bioarchaeological methods to help identify the partial remains of an individual inadvertently discovered at a quarry located in Haines, Alaska.

A human skull fragment was accidently discovered during the construction of a bald eagle mew. After discovery, SRSCORP attempted to recover the rest of the remains by excavating at the Bald Eagle Foundation and the 6.5-Mile Quarry. A large cranial fragment (frontal bone), several smaller cranial fragments, a small portion of the pelvis, two leg bones (femur and tibia), and a tooth were found during recovery. Although the remains are fragmentary and incomplete, SRSCORP was able to recover enough remains to assess age, sex, stature, and lifestyle.

Age is assessed by one of two ways: growth and development in children and young adults or the degeneration of bone in older adults. For instance, the two major leg bones, the femur and tibia, are fully developed and fused (meaning the cartilage at the ends of the bones had ossified and fused together) by the age of 22. Additionally, dentition is a good way to assess age because dental development occurs at relatively the same time, regardless of external pressures. One tooth, a premolar, was recovered from the 6.5-Mile excavation. Premolars erupt in the mouth by 11 years of age (+/- 30 months) and are in occlusion (in contact with the other teeth in the mouth) by 12 years (+/- 36 months). Since the premolar illustrated moderate to severe wear, we can deduce that the tooth was in occlusion for several years. The premolar, in conjunction with the fused long bones, indicates that the individual was a young-to-middle adult (22 years old at minimum).

Sex is usually assessed using the pelvis. Unfortunately, only a portion of the pelvis was recovered. Additionally, the small pelvic fragment was compromised from extreme water damage and post-mortem (after death) temperature fluctuation. To estimate sex, Sugimoto used a suite of reliable non-metric bone characteristics. The preliminary results showed that the skull illustrated both female and male characteristics, but had stronger male traits including a pronounced brow ridge and external occipital protuberance, which measures the robustness of the back of the head.

Stature was estimated using the femur and tibia. Because the bones were fragmented, the Steele and McKern (1969) method was used to estimate the maximum length of each bone before calculating the final stature estimation. Subsequently, the estimated bone lengths were used to estimate the stature by using formulae presented by Auerbach and Ruff (2110). The Auerbach and Ruff (2110) stature equations were specifically designed for Native North American groups and were developed using the known (recorded) height of modern populations. Sugimoto used population-specific equations for Arctic groups to calculate Arctic stature for males, females, and individuals whose sex is unknown. The results indicate that the Chilkat person was short, most likely ranging between 47 and 410 in height.

The condition of the leg bones help shed light on the lifestyle of the Chilkat person. The femur (upper leg bone) supports several muscles. Individuals with more muscle mass will develop robust muscle attachments on the bone. The Chilkat individual illustrated very robust muscle attachments on the femur, which indicates that the individual was active at the time of death and maintained very strong legs through their daily activities.

In conclusion, the Chilkat person found at 6.5-Mile Quarry was a probable male, young-to-middle adult, short (47-410), with robust muscle attachments indicating the individual had very strong legs. Moving forward, SRSinc hopes to further develop this research by implementing more ethnographic information about Tlingit division of labor, use anthropomorphic data to clarify the level of sexual dimorphism, and tie in regional biological research to elucidate the population trends in non-metric analyses.