Salt Drive in Beavers: An Experimental Assessment with Field Feeding Trials
September 2009 - December 2011
- Massachusetts Division of Fisheries and Wildlife
Salt drive is an extensively documented phenomenon that affects varied classes of herbivores worldwide. The conditions that are believed to trigger this response in other herbivores are also operant within the foraging ecology of beavers, but salt drive has not been investigated in this species. We used salt treated and untreated sticks of aspen and milled pine to set up feeding trials at several wetlands in Massachusetts. Beavers uniformly consumed all aspen sticks (both treated and untreated, with a slight indication of selecting the salted ones first). However, treated pine sticks were selected over untreated, but only after aspen was consumed. Our results indicate that beavers are attracted to salt, but do not appear to have the same strong drive for salt that other, more terrestrial, herbivores show. This is likely due to a combination of the physiology, diet, and semi-aquatic life history of beavers.