Squirrels CAN swim.
More Info: Tree squirrels such as the North American grey squirrel (Sciurus carolinensis) or the Eurasian red squirrel (Sciurus vulgaris) can swim, although they are not very strong swimmers. It is sometimes thought that they cannot swim because they are often found drowned in swimming pools, ornamental ponds and water troughs.
Squirrels swim mainly with their forelegs, although sometimes they will engage their hind legs. They keep their heads above water for as long as they can. Squirrels have been observed swimming ponds, streams, creeks or temporarily flooded areas. North American grey squirrels can swim up to two miles at one time.
One red squirrel in England was filmed trying to swim across a lake, but it began to tire about 300 yards into the lake. Fortunately, that squirrel was rescued before it drowned. That squirrel swam with its head and fluffy tail held out of the water.
Warning for Pool and Pond Owners
Since squirrels are not strong swimmers, they can easily drown in small bodies of water like a swimming pool. Many pools and water troughs have steep, smooth sides where a squirrel cannot climb out. They swim around in circles until they tire and drown. Pool and trough owners should always place a small ladder or even a length of rope into a pool or trough so a trapped squirrel can get out.
“Species Description – Wellesley.” Wellesley College – Wellesley College. N.p., n.d. Web. 1 Nov. 2012. http://www.wellesley.edu/Biology/Web/Species/asquirrelgray.html
“BBC NEWS | UK | England | Cumbria | Squirrel’s epic swim across lake.” BBC News – Home. N.p., n.d. Web. 1 Nov. 2012. http://news.bbc.co.uk/2/hi/uk_news/england/cumbria/7096816.stm