It has proved quite a challenge to identify the stage at which early man transitioned from short range (and dangerous) hunting by stabbing with a spear, and took the more pragmatic approach of throwing them from a safer distance The difficulty lies in identifying the different types of marks made on impact.
     Now an archaeology student from South East archaeology in Canberra (Australia), Corey O'Driscoll, has been studying them for his undergraduate thesis. He originally became interested after reading articles on the wounds caused to humans by medieval weapons. There have been several studies of this type, with claims for the earliest use of spears going back over 500,000 years but none of these were conclusive and raised strong doubts over their validity.
     Corey O'Driscoll decided to conduct his own experiments. He knapped spear and arrow heads and either fired from a bow or threw spears at a variety of sheep and cow carcasses. Then, after rotting or boiling the flesh away, he examined the marks made. Marks made by projectile weapons are quite distinctive from butchering marks, and show signs of either drag or fracture. He then noticed what proved to be a critical element. As the impact from these thrown weapons was fairly high velocity, minute fragments of the arrow or spear head broke off on impact and became embedded in the fracture or puncture mark. He then went on to examine mammal bones found at Pinnacle Point Cave in South Africa, which had also been found to have minute fragments of stone imbedded in the puncture marks, very similar to his experimental ones. These mammal bones have been dated between 91,000 and 98,000 years ago.
     This thesis could have substantial implications, prompting archaeologist Tina Manne, from the University of Queensland (Australia), to remark that they have "...Incredibly wide-ranging applicability and the potential to further our understanding of when this technology was adopted elsewhere."

Edited from Science (17 May 2013)