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1998--Did Paleoindians Cause Megafaunal Extinction in North America?


For this assignment I read "Blood Residues on Fluted Points from Eastern Beringia."  The article was co-authored by Thomas H. Loy of the University of Queensland and E. James Dixon of the Denver Museum of Natural History.


In this article Loy and Dixon seek to introduce new evidence regarding Paleoindian activities in arctic and subarctic North America.  Specifically, they explore to what role, if any, human predation played in the extinction of certain megafauna species of North America.


Loy and Dixon began by collecting, from museum archives, 36 fluted points which had come from various sites in Eastern Beringia.  They examined these to see which points might contain some kind of blood in the hopes that they would be able to match the blood to a specific species through DNA amplification or hemaglobin crystallization--they had several samples of dessicated megafaunal flesh (e.g. bison, moose, muskox, etc.) that would allow DNA comparison from the blood on the points. 

Unfortunately, Loy and Dixon were forced to discard 15 of their samples because they had been so thoroughly cleaned during curation as to render them useless in the investigation.  Of the remaining 21 points, another 6 had to be discarded because there was not enough blood residue to extract and analyze.  From the fifteen remaining points, they were able to identify 6 separate species--mammoth, modern bison, sheep, bear, caribou, and muskox.

Of these species, only the mammoth (Mammuthus primigenius) is currently extinct.   This would seem to indicate that humans did not play a significant role in the large scale extinction of North American megafauna.  However, the authors point out that their sample of points was not sufficient in size as to reach any definite conclusions.


To quote from the authors' abstract, "This is the first time a direct association has been made between the use of fluted projectile points and human predation of extinct fauna and other large Pleistocene mammals in arctic and subarctic North America."   This sounds very exciting, but it is rather bland.  Heavy emphasis should be placed on the "other large Pleistocene mammals," and the word "extinct" should be downplayed.  In truth, out of the fifteen points Loy and Dixon examined, only one contained blood from an extinct mefafaunal species.  The rest were from species that still exist today.  Consequently, one would be hard pressed to support, given the evidence in this article, a hyposthesis that determined human predation to be the sole cause of megafaunal extinction in North America.