Beavers build lodges as sheltered homes in rivers, streams, ponds and lakes. A lodge is a compact structure made from branches, sticks, vegetation and mud, usually with entrances that open underwater.
There are two main types. An open-water lodge is built on a platform of piled branches surrounded by water, while a bank lodge is dug into or beside a riverbank and reinforced with sticks and mud. Inside, the above-water living chamber provides protection from predators, weather and winter cold. An air hole may be left at the top, while underwater entrances let the beavers enter and leave discreetly.
Beavers also build dams, but a dam and a lodge are different structures. The dam slows or redirects flowing water, creating a deeper pond that makes the lodge safer and easier to access. If suitable building materials are scarce, beavers may instead live in bank burrows. Their lodges are therefore homes, while dams are landscape-changing water-control structures that help create the habitat around those homes.