Is the wisent (Bison bonasus) indigenous to the Netherlands and Belgium?
Some documents claim that the wisent (Bison bonasus) was present in north-western Europe during the Middle Ages. With the introduction of the wisent into Dutch nature management these claims are being repeated again. This article examines these claims and whether they tally. Bone finds would indisputably prove the former existence of the wisent in the Netherlands and Belgium. Records of bone finds show wisent did occur in north-western Europe in the Early Holocene, but no demonstrable wisent bones from the Middle and Late Holocene have been found in this area. The distribution of wisent bone finds in Europe shows that Bison bonasus mainly lived in central and eastern Europe. The spread of wisent toponyms in Germany also seems to reflect the preference of the wisent for a continental climate. This paper examines the written sources that make claims for the occurrence of the wisent in the Middle Ages in southern Sweden, England, Belgium and the Netherlands. It is clear that there are no reliable data. The claims partly arose due to name confusion with aurochs (Bos primigenius), partly through inaccurate interpretations of texts, and partly by people simply advancing unsubstantiated assertions. If the wisent occurred in the Netherlands and Belgium in the Middle and Late Holocene, it must have been just a rare vagrant, not a resident species.