Prehistoric blood residues: detection on tool surfaces and identification of species of origin.

Blood residues from several animal species have been discovered on the surfaces of chert, basalt, and obsidian prehistoric tools (1000 to 6000 years old) from open-air sites along the western coast and in the northern boreal forest of Canada. A screening test has been developed to detect residual blood. Hemoglobin has been crystallized from the residues, and the species of origin determined.