Generally land mammals, most squirrels have the ability to swim in dog paddle fashion. They use their long, bushy tails for steering, much as a boat uses a rudder. Typically, they go into the water only when the need arises.
Because of the fairly small size of most squirrels, they are not the greatest distance swimmers, and occasionally they drown if they do not reach the shore in time. Although most breeds, such as the red squirrel and the eastern gray squirrel, are able to swim, the flying squirrel cannot. The extra flaps that allow flying squirrels to glide in the air hinder them in the water.