Walk along Zurich's Limmat riverbank and you might notice something odd : fresh wood chips scattered on the footpaths, tooth marks carved into tree trunks, and entire riverside willows reduced to stumps . But this isn't vandalism, it's the work of Zurich's newest residents with serious engineering ambitions: European beavers are reshaping the city's riverbanks, one tree at a time. Their presence in Switzerland's largest city is a relatively recent phenomenon. After being completely eradicated from Switzerland's landscapes in the 19th century, the beaver is reclaiming not just rural areas, but also increasingly pushing into urban rivers and lakes 2 . Figure 1: Beaver reintroduction in Thurgau, 1968 © Archiv Anton Trösch The beaver's comeback in Switzerland began in the 1950s through the efforts of passionate individuals. Anton Trösch, for instance, imported six beavers from Norway in 1968 and released them in a lake in Cant...