tapir radius cut-marks

Sometimes it's difficult to distinguish between cut-marks from a chert tool and gnaw-marks from animal teeth.

Using scanning electron micrographs, Shipman (LIFE HISTORY OF A FOSSIL, 1981) demonstrated that butcher-marks have micro-striations within the groove. Gnaw-marks are smooth and rounded within the groove.

Here is an image of a tapir radius from the Santa Fe with butcher-marks. Can you see the fine auxillary cuts in the primary cut?

(This image is best viewed by clicking on the "options" button

on the upper right of this page => "view all sizes" => "large".)