Kanadischer Biber. Eine Biberburg in der Flußlandschaft, defekter Damm, schwimmender Biber beim Herbeischaffen von Ästen und Knüppeln, Zerschneiden von Ästen, Verankern des Materials durch Einrammen mit Zähnen und Vorderpfoten.

The film shows how a beaver (Castor fiber canadensis) closes the break of a dam. Branches and sticks are collected and fastened at the gap by the swimming animal. With its teeth and fore paws the beaver rams the pieces of wood deeply into the branchwork of the dam. The bigger sectional area of the boughs is always directed with the streaming, the smaller branched out parts of them are directed against it.