Unfortunately the real answer is "invisible" because there are no polar
bears at the south pole.
Alex. F. Burr
In a message dated 2/14/2012 1:23:05 P.M. Mountain Standard Time,
gould@usc.edu writes:
The answer, of coruse, is "white" because it's a polar bear. The man
started from the South Pole where EVERY direction is north, and walking
west meant that he never got further than a mile from the South Pole
before turning south.