* Otters: There are several species of otters, all of which are incredibly skilled swimmers and spend much of their time in the water. They have thick, waterproof fur that helps them stay warm.
* Beavers: These large rodents are famous for building dams and lodges in rivers and streams. They have thick, water-repellent fur and webbed hind feet that make them excellent swimmers.
* Muskrats: These smaller rodents are also semi-aquatic and often found in marshes and wetlands. They have dense fur and strong tails that help them navigate through water.
* Polar Bears: While they are primarily associated with icy environments, polar bears are actually excellent swimmers and spend a significant amount of time in the water hunting seals.
* Sea Otters: These are the smallest marine mammals and are known for their incredibly dense fur, which is the thickest of any mammal. They spend most of their time in the water.
There are many other animals that live in water and on land, but they don't have fur. For example, amphibians like frogs and salamanders have smooth, moist skin.