Recent excavations at the Grotte du Bison, Arcy-sur-Cure, demonstrate essential continuity in industrial succession from the late Mousterian into the Châtelperronian. The faunal assemblage, however, demonstrates considerable occupation by hyenas and bears in alternation with that by humans in the underlying Mousterian levels. This demonstrates one of the fundamental problems of cave stratigraphies. The archaeological record of the Middle Palaeolithic rarely presents unambiguous associations and spatial configuration. A substantial proportion of the Middle Palaeolithic archaeological record has been investigated in cave mouth and rock shelter sites. Cave taphonomy most often results in complex palimpsests of depositional history, mixing debris from prehistoric human occupations with those from other processes, both geological and faunal. Spatial analysis may be one way of deciphering portions of complex depositions. Data from one Middle Palaeolithic level of the Grotte du Bison are presented here to illustrate the potential for discerning differential activity and occupation areas resulting from Neanderthals, hyenas and other animals. Signatures of associations of bone fragments with other classes of material recovered from recent excavations are offered to identify those portions of the palimpsest attributable to human activities. Copyright © 2011 John Wiley & Sons, Ltd.