On the reliability of archaeological rat bone for radiocarbon dating in New Zealand

Holdaway & Beavan (1999) discussed the radiocarbon dating of bone of variou s species from the site of Hukanui Pool, Hawkes Bay. We question their conc lusion that two apparently reliable rat bone gelatin determinations from th e Hukanui Pool site provide support for the entire suite of rat determinati ons from previously dated 'natural' sites. We present evidence that contrad icts their conclusion that bone material from the broad range of archaeolog ical midden sites is generally less well-preserved than bone from 'natural' caves in New Zealand such as Hukanui Pool. We show that when dates from ar chaeological bone from Pleasant River and Shag River Mouth are evaluated, t he state of preservation is comparable with material from the 'natural' sit e of Hukanui Pool, and should provide accurate and reproducible radiocarbon determinations. Our conclusion has serious implications for the acceptance of the model proposed by Holdaway (1999), because if archaeological bone i s well-preserved but yields unreliable and unreproducible results, it is li kely that well-preserved 'natural' bone is similarly affected.