Climbing trees can be achieved using gaits similar to both the Dog walk and the Giraffe walk, while Squirrels actually gallop up trees. Squirrels are also unique in being able to walk down trees as well. The ankles on their hind legs are so flexible that they can turn through 180 degrees allowing them to be equally useful going up and coming down. Swimming - Many land mammals can swim, even and including the big cats. Even some bats can survive falling in the water.
Hamsters fill their cheek pouches with air before taking the plunge.
Some species are semi-aquatic and are equally at home in the water as on land, i.e. Otters, Hippopotamuses. For most terrestrial mammals, swimming involves walking in the water. In other words they use the same gait as they do on land. The more fully aquatic species are, however, more adapted to the water. Beavers fold their front legs under their chests while swimming.