Scanning electron microscopy of mammalian bloodstains on lithics

What is it about?

In a simulation of a prehistoric predation human operative chain, mammalian bloodstains on palaeolithic-like chert implements were obtained from two specimens belonging to 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 one were coated with gold and then examined by a scanning electron microscope.

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Why is it important?

The presence of morphologically complete mammalian 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 an evidence of the real use of this on an animal resource, the presence of RBC in a smear is an evidence as being blood. Results revealed the presence of preserved RBC with several shapes as those found in haematological studies, as well as moon-like shapes and negative replicas, two bloodstain-characteristic morphologies which are interpreted as due, respectively, to erythrocyte-plasma interaction when drying and to imprinting by dried plasma matrix.