Bone survival: The effects of sedimentary abrasion and trampling on fresh and cooked bone

Abstract

AbstractIt is commonly assumed that, at least when considering similar sized animals, the bones from all taxa stand an equal chance of preservation. This paper summarizes one aspect of a larger study undertaken in order to assess whether this assumption is true, based on the results of experiments and observations into the effects of a range of pre‐depositional processes. The rates of bone destruction by sedimentary abrasion and by trampling are determined for small mammal, fish and frog bones. Patterns of bone loss and fragmentation are examined both between species and within the skeleton, for fresh and boiled bone. It is shown that there is considerable interspecies variation in the ability of bones to withstand these physical forces. Frog bone proved particularly resistant, while within the fish, bone from the Gadidae was less resilient than might be expected, given its predominance in British Medieval archaeological sites and coastal sites of all periods. Within the skeleton, bone shape appears to be a very important determinant of relative survival. Boiling dramatically reduces bone's resistence to destruction. The physical properties of fresh, boiled and burnt bone are compared mechanically, and the dramatic loss of strength induced by heating is demonstrated. The often voiced assumption that fish bone is more prone to destruction than mammal bone is shown to have some validity. The results add more evidence to support the view that comparison of species abundance by fragment counts may not always be appropriate, and that interpretation of skeletal element frequencies should be approached with caution.