Though they share similar habitats, distinguishing between beavers vs. otters is easy because they differ in appearance and behavior. For example, otters are longer and slimmer than heavier, stockier beavers and are known to be agile swimmers. Another noticeable difference is the tail. Beavers are well-known for their large, paddle-like tails that can be heard slapping the water from time to time. On the other hand, otters have long, round tails completely covered in fur.