Use of anal gland secretion to distinguish the two beaver species Castor canadensis and C-fiber

Introduced North American beavers Castor canadensis pose a potential threat to the continuing recovery of Eurasian beaver C. fiber populations in seve ral European countries. For management purposes, it is necessary to be able to identify and distinguish the two species. This, however, is difficult b ecause the two species are morphologically, ecologically and behaviourally similar. To find a method for species identification, we examined the possi bility of using anal gland secretion (AGS) collected from the two beaver sp ecies. We asked 20 inexperienced volunteers to inspect the colour and visco sity of the AGS. When we provided the volunteers with the sex of each beave r and descriptions of the colour and viscosity of AGS from males and female s of the two species, all volunteers could 100% correctly identify the two species. We therefore conclude that the colour and viscosity of the AGS can be used for a quick and easy identification of the two beaver species.