I live in British Columbia, where we are proud to be home of a large number (essentially all) of the white black bears.  They are generally known as Sprit, or Kermode Black bears here in BC.  As per general education to the public, the cause of the spirit bears white fur is caused by a recessive gene, similar to the idea of how a human can have red hair.  The white form of black bears is essentially a hold over from the ice age.  In British Columbia, most spirit bears are found on one (large) island on the Central coast, Princess Royal Island, however they do occure everywhere occasionally.    