Taphonomy of tortoises deposited by birds and Bushmen

In the semi-arid Karoo of South Africa's central plateau, tortoises are com monly preyed upon by raptors, some of which roost on ledges in the backs of small rock shelters. In the past, any suitable ledge could be occupied onl y when the shelter was not in use by Bushman hunter-gatherers. Thus, both a gents could have contributed tortoise elements to the faunal deposits which accumulated int he shelter fills over the past two millennia. Element surv ival and breakage rates of tortoise remains in a recent shelter roost accum ulation show reversed frequencies to those for tortoise carcasses left a ra ptor kill sites: what is abundant at the roost (skeletal elements, particul arly from the neck and head) are scarce at the kills. When the roost sample is compared with the Bushman foodwaste sample beneath it, the two are read ily distinguished by their element composition and condition. A surface sam ple from a neighbouring shelter without roosting ledges is also rich in ske letals, but lacks the characteristic cranials and vertebrae. Small carnivor es are the suspected non-human agents. Although radiocarbon dates indicate an earlier hiatus in this sequence, no such raptor-like tortoise assemblage s are detectable at this level.