Explain why beavers build dams?

To protect themselves from predators

Beavers build their dams mainly to create an effective physical barrier against predators like wolves or coyotes. By forming a sort of artificial lake around their lodge, they make their home less accessible to animals that swim poorly. The dam thus increases security at the entrance of the lodge where the young and their family live. Thanks to the deep water, beavers can dive quickly and discreetly in case of danger, easily escaping attacks.

To create a favorable habitat

By building dams, beavers create the formation of deep and calm ponds. This stagnant water allows these aquatic builders to access their submerged burrows safely. In this tranquil environment, they arrange their shelters, called lodges, with nearly invisible underwater entrances for their enemies. These wet habitats also promote the proliferation of aquatic plants, which are useful for easy feeding. They thus create a small tailor-made paradise, perfectly meeting their daily needs.

To facilitate food searching

By creating a pond with their dam, beavers flood the surrounding area to better access their favorite food: the branches, leaves, and bark of trees close to the water, such as willows or poplars. They dive and swim much more easily to submerged trees to gather their sustenance in peace, and also store supplies underwater for the winter. The aquatic access also allows them to transport pieces of wood more easily without having to travel long distances on land, which are often risky due to predators.

To regulate water levels

Beavers are a bit like the natural engineers of waterways. With their dams, they control the water level by creating small reservoirs. This helps maintain a stable and safe depth near their habitat. When the water is too low, the dam holds back a sufficient reserve; when there is too much water, it slows down and distributes the flow, thereby limiting the risks of flooding or extreme drying out. It's convenient: by managing the level in this way, they stabilize their entire little ecosystem to live quietly and comfortably.

To mark and defend their territory.

Beavers are territorial animals, and their dams also serve to visually mark the boundaries of their territory. These constructions directly signal to intruders: "Hey dude, you're entering my place!" Additionally, they regularly add castoreum to their structures, a particular scent that clearly communicates to other beavers: this is our home, go somewhere else! Thus, their dams play a central role by serving both as physical barriers and very effective olfactory markers to defend their area.