Encounters between Otters (Lontra canadensis) and American Beavers (Castor canadensis)

Six encounters between otters (Lontra canadensis) and American beavers (Castor canadensis) were observed between 1997 and 2003 at Wellesley Island State Park, New York. Contrary to the observer’s expectations, in each case the beaver moved aggressively toward the otter or otters, and the otters retreated. The author offers detailed accounts of each of the interactions, which may offer some insight into the relationship between otters and beavers. In half of the encounters, the beaver appeared to the observer to be intent on keeping otters away from its lodge. The beaver was not, however, always successful.