The ferret appears in some medieval encyclopedias. It has a color between white and brown and is a little larger than a weasel. The animals were placed by hunters in the caves in which rabbits hide, where they attack the beasts with their bites, until they drive them out of the cave and into the net. They also attack whatever animal that breathes, no matter how big it is.

The names mygale and migale are used for the shrew in Liber de natura rerum, the encyclopedia by Thomas of Cantimpré.

The furunculus may be the Euopean ferret, which was used to hunt rabbits.