James T. Anderson and Dr. Joel C. Janetskik, Anthropology

Mortality profiles (ages at death) constructed from the faunal analysis of archaeological sites offer unique insights into specific cultural predatory patterns and lifeways of the sites former inhabitants. The products of prey age selection or mortality profiles allow archaeologists to understand strategies of hunting, land use, and “habitual techniques of procurement” . A mortality profile of 4 mule deer (Odocoileus hemionus) was created from the thousands of identified bones excavated at Aspen Shelter, Utah in an attempt to understand such cultural adaptations.

To create the mortality profile the mule deer were aged by counting growth increments or cementum annuli visible in the cementum pad of the M1 and M2 mandibular molars. These rings, similar to the rings of a tree, are laid down in alternate light (summer) and dark (winter) rings, as seen in cross section. To obtain adequate cross sections the teeth were first removed from the mandible and then cut transversely with 1.0″ fiberglass or 7/8″ aluminum oxide cutting wheel through the root to expose the cementum pad. If necessary the tooth was then ground with a fine grain porcelain grinder and wet with a 70% alcohol solution. All teeth were viewed under a dissecting microscope using various intensities of reflected light.2

Of the nearly 100 teeth cut, the “annuli” rings were detected in nearly 70%. Two factors contributed to the apparent lack of rings in the remaining 30%. The first was the result of the teeth being deciduous or immature creating a hollow or non-existent root cavity. But more decisively was the amount or lack of preservation. Exposure of the root to changing degrees of moisture over time appears to destroy the visible rings of the cementum pad. This destruction may result from bioturbation, site vandalism, or even improper preparatory cleaning.

Each tooth in the profile is represented by an “estimate” age and an “actual” age and categorized into one of six age groups. Before each mandible was cut it was aged according to general eruption and wear patterns, thus becoming the age estimate. The necessary tooth was then cut and the identifiable rings represent the actual age. These categories were necessary due to the destructive nature of the aging process.

Over 75% of the aged teeth were found in two late archaic levels, with 15% being disturbed levels and 9% associated with a possible Fremont occupation. This result allows for a synchronic explanation of the cultural predatory patterns of the well represented archaic period, radio carbon dated from 1685 B.C. to 30 A.D 1. Of the 68 teeth aged in this level, 68% of the age “estimate” teeth and 69% of the “actual” teeth were found to be in one of the three immature age groups. With 24% of these archaic teeth being unknown (undecipherable) we find that only 8% are from mature aged deer. This overrepresentation archaeologically of young and immature deer represents what is termed an attritional or U shaped (in this case “L” shaped) age profile 4. Archaeologically this translates into scavenging, or selectively hunting by humans the most vulnerable or weakest animals 3. Though this pattern is a common result of natural death and predation, the apparent lack of an over-representation of old aged deer – which is usually associated with this mortality profile does create questions that may only be answered by further faunal analysis and ungulate aging.

An interesting product of the research which may support current theories of the sites function is the amount of teeth ending in dark rings. Odocoileus hemionus fawns are born between the months of April and June resulting in the first ring being white for the summer and then a small dark ring representing the first fall or winter. An animal that died in the fall of its first year would be aged as .5 yrs, the next fall as 1.5 yrs., etc. Of the 89 teeth aged nearly 80% had a final dark “annuli” ring announcing that the animal had been killed near the end of the year. This data supports the idea that the Aspen Shelter site functioned more as a seasonal hunting camp and not as year round residential site.

References

1. Crosland, R. n.d. An Analysis of the Faunal Remains from Aspen Shelter. Brigham Young University.
2. Ransom, A.B. 1966. J. Wildle. Manage. 30.1: 197-199.
3. Renfrew, C., and Paul Bahn. 1990 Archaeology: Theories, Methods, and Practice. Thames and Hudson Ltd.
4. Stiner, M.C. J. Of’Anthro. Archaeology 9: 305-351.