A recent visit to the impressive Knapdale beaver re-introduction trial triggered throughts of how beavers modified the environment, effectively managing woodlands and water bodies, and the traces they would leave in the archaeological record. Beavers went extinct in Scotland apparently sometime between the 12th and 16th centuries, probably due to hunting (see Conroy & Kichener PDF at the SNH link). Beaver-knawed wood has been found on English archaeological sites, as discussed in Bryony Coles’ book on beavers in Britain’s past, and beaver bones are reported from under peat in a number of locations in Scotland, probably early-mid Holocene (see Conroy & Kitchener paper as above).
It is important for Scottish archaeologists to recognise evidence of beaver activity, because they were here for most of human history, and their works are so sophisticated that they could be mistaken for the creation of human hands.