Beavers are the builders within the animal kingdom, and they have massive chisel-shaped teeth, which allow them to cut and peel wood branches. Also, their teeth have an outer orange coating, which is from iron, replacing the calcium in their teeth. Their lips are lined with fur and this combined with folds of skin that close over openings allows them to swim underwater being airtight while carrying branches under water.
Beavers construct dams a short distance from their homes to keep their predators away from them. The dams produce wetland habitats for fish, and they also keep oil from spilling into the river, which is often helpful for preserving the environment. Beavers are indigenous to Europe, North America, and Asia.