You can read more about what the Bestiary† from the middle of the 13th Century had to say about beavers at http://photos.tandlphotos.com/blog/2016/1/castor-canadensis

 

†Image from Bestiary MS Bodley 764. Page 43. “Bestiary being an English version of the Bodleian Library, Oxford M.S. Bodley 764 with all the original miniatures reproduced in Facsimile. Translated and introduced by Richard Barber. The Boydell Press. Woodrifge. 1999”