Experimental SEM Determination of Game Mammalian Bloodstains on Stone Tools

The presence of morphologically complete mammalian erythrocytes (red blood cells, RBC) from bloodstains has been previously evidenced in prehistoric implements. While the presence of ancient non-human blood on a prehistoric tool is evidence of the real use of this on an animal resource, the presence of RBC in a smear is evidence of blood. In a simulation of a prehistoric predation human operative chain, mammalian bloodstains on palaeolithic-like chert implements were obtained from two specimens belonging to the order Artiodactyla: collared peccary (Tayassu tajacu, family Tayassuidae) and Dorcas gazelle (Gazella dorcas, family Bovidae). After one year, the unburied peccary blood smear and the buried gazelle smear were coated with gold and then examined by a scanning electron microscope. Results revealed the presence of preserved RBC with several shapes like those found in haematological studies, as well as curved plasma fractures and negative imprints, two bloodstain-characteristic morphologies which are interpreted as due, respectively, to erythrocyte-plasma interaction when drying and to imprinting by dried plasma matrix.