Beaver dams can completely reroute a river’s course

Evidence

The Fall River has had its source completely altered by the operations of the beavers. Their engineering skill is wonderful. In one place they have made a lake by damming up the stream; in another their works have created an island, and they have made several falls. Their store-houses, of course, are carefully concealed. By this time they are about full for the winter. We saw quantities of young cotton-wood and aspen trees, with stems about as thick as my arm, lying where these industrious creatures have felled them ready for their use. They always work at night and in concert. Their long, sharp teeth are used for gnawing down the trees, but their mason-work is done entirely with their flat, trowel-like tails. — Isabella L. Bird, A Lady’s Life in the Rocky Mountains, 486

Categorization

• XREF: Feeds the reader’s stated interest in abundant wildlife observations in the Rocky Mountains.