Close to the village of Ferch, municipality of Potsdam (Brandenburg, Germany) the local railway runs between the river Havel and the lake Schwielowsee. The local authorities experienced some problems with erosion of the slopes because of the presence of many Beavers. A thriving beaver population is threatening the stability of the Germany´s dams and slopes. Many wildlife groups work togehter with engineers to find out how to protect these important infrastructures from the small but potentially destructive semi-aquatic rodents. Since already over 40 years the beaver population has grown exponentially.