Reply to Evans: Use of poison remains the most parsimonious explanation for Border Cave castor bean extract

Evans (1) challenges our interpretation (2) that the presence of ricinoleic and ricinelaidic acids on a notched stick from Border Cave reflects the use of poison 24,000 B.P. We find his alternative hypotheses unlikely and reject his critiques of our methodology. He acknowledges the similarity of the notched stick to San poison applicators but ignores this similarity in his later arguments. Had the castor bean extract been found on another object, a stronger case may have been made for a function other than poison; the presence of it on a stick, virtually identical to those used by San for applying poison, cannot be dismissed.