Low-temperature-induced bone shrinkage: a controlled study using kangaroo femora

Abstract

The taphonomic effects of weathering and heat-induced transformation of bone have been intensively studied over the last century. These two processes share a common agent of change in the form of bone desiccation. A study was devised to test the hypothesis that significant bone shrinkage could be achieved by prolonged exposure to low (30°C) temperatures. The methodological approach involved placing fresh Eastern Grey Kangaroo long bones (n = 6) in an industrial oven at 30°C for a period of 39 days, with changes monitored every 24 h. Long bones were comprehensively measured to determine the extent of shrinkage during the desiccation process. The results indicated that the long bones displayed statistically significant amounts of shrinkage in all regions, with the majority of change occurring within the first 10 days of the drying period. It is concluded that exposure to a dry environment, at 30°C, can cause desiccation within 24 h in some cases, inducing dimensional changes that could potentially affect the results of a range of osteometric techniques. It is also apparent that the effects of prolonged exposure to low temperatures are similar to heat-induced changes seen in short-term exposure at high temperatures.

Keywords:

• forensic anthropology
• desiccation
• taphonomy

Acknowledgements

Thank you to the Australian National University for the use of their facilities. Thank you also to Catherine Fitzgerald and Juliet Meyer for their considerable help and advice during the conception and experimental phase of this paper.